The Mercedes-Benz first series of automatic transmission was produced from 1961 to 1983 in 4- and 3-speed variants for Mercedes-Benz passenger cars . In addition, variants for commercial vehicles were offered until the mid-1990s.
This transmission was the first Mercedes-Benz automatic transmission in-house developing.[ 1] semi-automatic systems like a vacuum-powered shifting for overdrive or the "Hydrak" hydraulic automatic clutch system. Alternatively, they bought automatic transmissions of other vendors, such as the Detroit gear 3-speed automatic transmission from BorgWarner for the 300 c and 300 d (not to be confused with the later 300 D and its successors).
The automatic transmissions are for engines with longitudinal layout for rear-wheel-drive layout passenger cars . The control of the fully automatic system is fully hydraulic and it uses electrical wire only for the kickdown solenoid valve and the neutral safety switch.
Physically, it can be recognized for its pan which uses 16 bolts.
Key Data
Gear Ratios[ a]
Model
Type
First
Gear
Total Span
Avg.
Components
Nomenclature
R
1
2
3
4
Nomi-
Effec-
Cen-
Total
per[ b]
Cou-
Gears
Ver-
Maximum Input Torque
K4A 025
w/o
1961[ 2] [ A]
−4.145
3.979
2.520
1.579
1.000
3.979
3.979
1.995
1.585
2 Gearsets
2.000
K[ c]
4[ b]
A
25 kp⋅m (181 lb⋅ft )
K4B 050[ d]
w/o
1964[ e]
−4.145
3.979
2.459
1.579
1.000
3.979
3.979
1.995
1.585
3 Gearsets
2.000
K[ c]
4[ b]
B
50 kp⋅m (362 lb⋅ft )
K4C 025
722.2
1967[ B] [ B]
−5.478
3.983
2.386
1.461
1.000
3.983
3.983
1.996
1.585
K[ c] [ c] [ f] [ 4]
4[ b]
C
25 kp⋅m (181 lb⋅ft )kp⋅m (289 lb⋅ft )kp⋅m (181 lb⋅ft )
W4A 018[ g]
720.1
1975
−5.499
4.006
2.391
1.463
1.000
4.006
4.006
2.001
1.588
W[ f]
4[ b]
A
18 kp⋅m (130 lb⋅ft )
W4B 035[ h]
TBD
1975
−5.881
4.176
2.412
1.462
1.000
4.176
4.176
2.043
1.610
W[ f]
4[ b]
B
35 kp⋅m (253 lb⋅ft )
W3A 040[ i]
720.0
1971
−1.836
2.306
1.461
1.000
2.306
1.836
1.519
1.519
2 Gearsets
2.333
W[ f]
3[ b]
A
40 kp⋅m (289 lb⋅ft )kp⋅m (362 lb⋅ft )kp⋅m (405 lb⋅ft )
K4A 025 transmission left hand side view K4A 025 transmission right hand side view
Layout
The K4A 025 is the first of the series, launched in April 1961 for the W 111 220 SEb , later replaced with the more reliable K4C 025 (type 722.2). It is a 4-speed unit and uses fluid coupling (also referred in some manuals as hydraulic/automatic clutch).
The design of the transmission results in poor shifting comfort, which does not meet Mercedes-Benz standards. This applies in particular to the change from 2nd to 3rd gear (and vice versa), which requires a group change, i.e. affects all shift elements.
Specifications
For this first 4-speed model[ a] [ b]
Gear Ratio Analysis[ c]
In-Depth Analysis[ d] [ e] [ f]
Planetary[ g]
Count
Nomi-[ h] [ i]
Cen-[ j]
Simple
Avg.[ k]
Model
Version
S1 [ l] 1 [ m]
S2 [ n] 2 [ o]
Brakes
Ratio
Gear[ p]
Gear
R
1
2
3
4
Gear[ d]
i
R
{\displaystyle {i_{R}}}
[ d]
i
1
{\displaystyle {i_{1}}}
[ d]
i
2
{\displaystyle {i_{2}}}
[ d]
i
3
{\displaystyle {i_{3}}}
[ d]
i
4
{\displaystyle {i_{4}}}
[ d]
Step[ p]
−
i
R
i
1
{\displaystyle -{\frac {i_{R}}{i_{1}}}}
[ q]
i
1
i
1
{\displaystyle {\frac {i_{1}}{i_{1}}}}
i
1
i
2
{\displaystyle {\frac {i_{1}}{i_{2}}}}
[ r]
i
2
i
3
{\displaystyle {\frac {i_{2}}{i_{3}}}}
i
3
i
4
{\displaystyle {\frac {i_{3}}{i_{4}}}}
Δ Step[ s] [ t]
i
1
i
2
:
i
2
i
3
{\displaystyle {\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}}
i
2
i
3
:
i
3
i
4
{\displaystyle {\tfrac {i_{2}}{i_{3}}}:{\tfrac {i_{3}}{i_{4}}}}
Shaft
i
1
i
R
{\displaystyle {\frac {i_{1}}{i_{R}}}}
i
1
i
1
{\displaystyle {\frac {i_{1}}{i_{1}}}}
i
1
i
2
{\displaystyle {\frac {i_{1}}{i_{2}}}}
i
1
i
3
{\displaystyle {\frac {i_{1}}{i_{3}}}}
i
1
i
4
{\displaystyle {\frac {i_{1}}{i_{4}}}}
Δ Shaft[ u]
0
−
i
1
i
R
{\displaystyle 0-{\frac {i_{1}}{i_{R}}}}
i
1
i
1
−
0
{\displaystyle {\tfrac {i_{1}}{i_{1}}}-0}
i
1
i
2
−
i
1
i
1
{\displaystyle {\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}}
i
1
i
3
−
i
1
i
2
{\displaystyle {\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}}
i
1
i
4
−
i
1
i
3
{\displaystyle {\tfrac {i_{1}}{i_{4}}}-{\tfrac {i_{1}}{i_{3}}}}
Efficiency
η
n
{\displaystyle \eta _{n}}
[ f]
T
2
;
R
T
1
;
R
:
i
R
{\displaystyle {\tfrac {T_{2;R}}{T_{1;R}}}:{i_{R}}}
T
2
;
1
T
1
;
1
:
i
1
{\displaystyle {\tfrac {T_{2;1}}{T_{1;1}}}:{i_{1}}}
T
2
;
2
T
1
;
2
:
i
2
{\displaystyle {\tfrac {T_{2;2}}{T_{1;2}}}:{i_{2}}}
T
2
;
3
T
1
;
3
:
i
3
{\displaystyle {\tfrac {T_{2;3}}{T_{1;3}}}:{i_{3}}}
T
2
;
4
T
1
;
4
:
i
4
{\displaystyle {\tfrac {T_{2;4}}{T_{1;4}}}:{i_{4}}}
Torque[ e]
μ
R
{\displaystyle \mu _{R}}
[ e]
μ
1
{\displaystyle \mu _{1}}
[ e]
μ
2
{\displaystyle \mu _{2}}
[ e]
μ
3
{\displaystyle \mu _{3}}
[ e]
μ
4
{\displaystyle \mu _{4}}
[ e]
Efficiency
η
n
{\displaystyle \eta _{n}}
[ f]
μ
R
i
R
{\displaystyle {\frac {\mu _{R}}{i_{R}}}}
[ f]
μ
1
i
1
{\displaystyle {\frac {\mu _{1}}{i_{1}}}}
[ f]
μ
2
i
2
{\displaystyle {\frac {\mu _{2}}{i_{2}}}}
[ f]
μ
3
i
3
{\displaystyle {\frac {\mu _{3}}{i_{3}}}}
[ f]
μ
4
i
4
{\displaystyle {\frac {\mu _{4}}{i_{4}}}}
[ f]
K4A 025
25 kp⋅m (245 N⋅m ; 181 lb⋅ft )[ 2] [ A]
50
44
3
3.9789
1.9947
1.5846 [ p]
Gear
R
1
2
3
4
Gear[ d]
−4.1455
−
228
55
{\displaystyle -{\tfrac {228}{55}}}
3.9789
378
95
{\displaystyle {\tfrac {378}{95}}}
2.5200 [ p] [ t]
63
25
{\displaystyle {\tfrac {63}{25}}}
1.5789 [ p]
30
19
{\displaystyle {\tfrac {30}{19}}}
1.0000
1
1
{\displaystyle {\tfrac {1}{1}}}
Step
1.0418
1.0000
1.5789 [ p] 1.5960 [ p] 1.5789
Δ Step[ s]
0.9893 [ t] 1.0108
Speed
-0.9598
1.0000
1.5789
2.5200
3.9789
Δ Speed
0.9598
1.0000
0.5789
0.9411
1.4589
Torque[ e]
–4.0111
3.9021
2.4896
1.5674
1.0000
Efficiency
η
n
{\displaystyle \eta _{n}}
[ f]
0.9676
0.9807
0.9879
0.9927
1.0000
Actuated Shift Elements
Brake B1[ v]
❶
❶
Brake B2[ w]
❶
❶
Brake B3[ x]
❶
Clutch K1[ y]
❶
❶
Clutch K2[ z]
❶
❶
Clutch K3[ aa]
❶
Geometric Ratios: Speed Conversion
Gear[ d] [ ab] [ ac]
i
R
=
−
R
1
(
S
2
+
R
2
)
S
1
S
2
{\displaystyle i_{R}=-{\frac {R_{1}(S_{2}+R_{2})}{S_{1}S_{2}}}}
i
2
=
S
1
+
R
1
S
1
{\displaystyle i_{2}={\frac {S_{1}+R_{1}}{S_{1}}}}
i
4
=
1
1
{\displaystyle i_{4}={\frac {1}{1}}}
i
R
=
−
R
1
S
1
(
1
+
R
2
S
2
)
{\displaystyle i_{R}=-{\tfrac {R_{1}}{S_{1}}}\left(1+{\tfrac {R_{2}}{S_{2}}}\right)}
i
2
=
1
+
R
1
S
1
{\displaystyle i_{2}=1+{\tfrac {R_{1}}{S_{1}}}}
Gear[ d] [ ab] [ ac]
i
1
=
(
S
1
+
R
1
)
(
S
2
+
R
2
)
S
1
R
2
{\displaystyle i_{1}={\frac {(S_{1}+R_{1})(S_{2}+R_{2})}{S_{1}R_{2}}}}
i
3
=
S
2
+
R
2
R
2
{\displaystyle i_{3}={\frac {S_{2}+R_{2}}{R_{2}}}}
i
1
=
(
1
+
R
1
S
1
)
(
1
+
S
2
R
2
)
{\displaystyle i_{1}=\left(1+{\tfrac {R_{1}}{S_{1}}}\right)\left(1+{\tfrac {S_{2}}{R_{2}}}\right)}
i
3
=
1
+
S
2
R
2
{\displaystyle i_{3}=1+{\tfrac {S_{2}}{R_{2}}}}
Kinetic Ratios: Torque Conversion
Torque[ e]
μ
R
=
−
R
1
S
1
η
0
(
1
+
R
2
S
2
η
0
)
{\displaystyle \mu _{R}=-{\tfrac {R_{1}}{S_{1}}}\eta _{0}\left(1+{\tfrac {R_{2}}{S_{2}}}\eta _{0}\right)}
μ
2
=
1
+
R
1
S
1
η
0
{\displaystyle \mu _{2}=1+{\tfrac {R_{1}}{S_{1}}}\eta _{0}}
μ
4
=
1
1
{\displaystyle \mu _{4}={\tfrac {1}{1}}}
Torque[ e]
μ
1
=
(
1
+
R
1
S
1
η
0
)
(
1
+
S
2
R
2
η
0
)
{\displaystyle \mu _{1}=\left(1+{\tfrac {R_{1}}{S_{1}}}\eta _{0}\right)\left(1+{\tfrac {S_{2}}{R_{2}}}\eta _{0}\right)}
μ
3
=
1
+
S
2
R
2
η
0
{\displaystyle \mu _{3}=1+{\tfrac {S_{2}}{R_{2}}}\eta _{0}}
^ plus 1 reverse gear
^ 2 simple planetary gearsets , 3 brakes, 3 clutches
^ Revised 14 January 2026Nomenclature
S
n
=
{\displaystyle S_{n}=}
R
n
=
{\displaystyle R_{n}=}
C
n
=
{\displaystyle \color {gray}{C_{n}=}}
carrier or planetary gear carrier (not needed)
s
n
=
{\displaystyle s_{n}=}
r
n
=
{\displaystyle r_{n}=}
c
n
=
{\displaystyle c_{n}=}
n
=
{\displaystyle n=}
i
n
=
{\displaystyle i_{n}=}
ω
1
;
n
=
ω
t
=
{\displaystyle \omega _{1;n}=\omega _{t}=}
ω
2
;
n
=
{\displaystyle \omega _{2;n}=}
T
1
;
n
=
T
t
=
{\displaystyle T_{1;n}=T_{t}=}
T
2
;
n
=
{\displaystyle T_{2;n}=}
μ
n
=
{\displaystyle \mu _{n}=}
η
n
=
{\displaystyle \eta _{n}=}
i
0
=
{\displaystyle i_{0}=}
η
0
=
{\displaystyle \eta _{0}=}
^ a b c d e f g h i j Gear Ratio (Transmission Ratio)
i
n
{\displaystyle i_{n}}
The gear ratio
i
n
{\displaystyle i_{n}}
is the ratio of
input shaft speed
ω
1
;
n
{\displaystyle \omega _{1;n}}
to output shaft speed
ω
2
;
n
{\displaystyle \omega _{2;n}}
and therefore corresponds to the reciprocal of the shaft speeds
i
n
=
1
ω
2
;
n
ω
1
;
n
=
ω
1
;
n
ω
2
;
n
=
ω
t
ω
2
;
n
{\displaystyle i_{n}={\frac {1}{\frac {\omega _{2;n}}{\omega _{1;n}}}}={\frac {\omega _{1;n}}{\omega _{2;n}}}={\frac {\omega _{t}}{\omega _{2;n}}}}
^ a b c d e f g h i j Torque Ratio (Torque Conversion Ratio)
μ
n
{\displaystyle \mu _{n}}
The torque ratio
μ
n
{\displaystyle \mu _{n}}
is the ratio of
output torque
T
2
;
n
{\displaystyle T_{2;n}}
to input torque
T
1
;
n
{\displaystyle T_{1;n}}
minus efficiency losses
and therefore corresponds (apart from the efficiency losses) to the reciprocal of the shaft speeds too
μ
n
=
i
n
η
n
;
η
0
=
ω
1
;
n
η
n
;
η
0
ω
2
;
n
=
T
2
;
n
η
n
;
η
0
T
1
;
n
{\displaystyle \mu _{n}=i_{n}\eta _{n;\eta _{0}}={\frac {\omega _{1;n}\eta _{n;\eta _{0}}}{\omega _{2;n}}}={\frac {T_{2;n}\eta _{n;\eta _{0}}}{T_{1;n}}}}
whereby
η
n
;
η
0
{\displaystyle \eta _{n;\eta _{0}}}
0
≤
η
n
;
η
0
≤
1
{\displaystyle 0\leq \eta _{n;\eta _{0}}\leq 1}
^ a b c d e f g h i Efficiency
The efficiency
η
n
{\displaystyle \eta _{n}}
from the torque ratio
in relation to the gear ratio (transmission ratio)
η
n
=
μ
n
i
n
{\displaystyle \eta _{n}={\frac {\mu _{n}}{i_{n}}}}
Power loss for single meshing gears
is in the range of 1 % to 1.5 %
helical gear pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range
spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range Corridor for torque ratio and efficiency
in planetary gearsets, the stationary gear ratio
i
0
{\displaystyle i_{0}}
is formed via the planetary gears and thus by two meshes
for reasons of simplification, the efficiency for both meshes together is commonly specified there
the efficiencies
η
0
{\displaystyle \eta _{0}}
stationary ratio
i
0
{\displaystyle i_{0}}
of
η
0
=
0.9800
{\displaystyle \eta _{0}=0.9800}
and
η
0
=
0.9700
{\displaystyle \eta _{0}=0.9700}
for both interventions together
The corresponding efficiency
for single-meshing gear pairs is
η
0
1
2
{\displaystyle {\eta _{0}}^{\tfrac {1}{2}}}
at
0.9800
1
2
=
0.98995
{\displaystyle 0.9800^{\tfrac {1}{2}}=0.98995}
and
0.9700
1
2
=
0.98489
{\displaystyle 0.9700^{\tfrac {1}{2}}=0.98489}
^ Layout
Input and output are on opposite sides
Planetary gearset 1 is on the input (turbine) side
Input shafts is S1 and, if actuated, C1
Output shaft is C2 ^ Total Ratio Span (Total Gear/Transmission Ratio) Nominal
ω
2
;
n
ω
2
;
1
=
ω
2
;
n
ω
2
;
1
ω
2
;
n
ω
2
;
1
ω
2
;
1
ω
2
;
n
=
1
ω
2
;
1
1
ω
2
;
n
=
ω
t
ω
2
;
1
ω
t
ω
2
;
n
=
i
1
i
n
{\displaystyle {\frac {\omega _{2;n}}{\omega _{2;1}}}={\frac {\frac {\omega _{2;n}}{\omega _{2;1}\omega _{2;n}}}{\frac {\omega _{2;1}}{\omega _{2;1}\omega _{2;n}}}}={\frac {\frac {1}{\omega _{2;1}}}{\frac {1}{\omega _{2;n}}}}={\frac {\frac {\omega _{t}}{\omega _{2;1}}}{\frac {\omega _{t}}{\omega _{2;n}}}}={\frac {i_{1}}{i_{n}}}}
A wider span enables the
downspeeding when driving outside the city limits
increase the climbing ability
when driving over mountain passes or off-road
or when towing a trailer ^ Total Ratio Span (Total Gear Ratio/Total Transmission Ratio) Effective
ω
2
;
n
m
a
x
(
ω
2
;
1
;
|
ω
2
;
R
|
)
=
m
i
n
(
i
1
;
|
i
R
|
)
i
n
{\displaystyle {\frac {\omega _{2;n}}{max(\omega _{2;1};|\omega _{2;R}|)}}={\frac {min(i_{1};|i_{R}|)}{i_{n}}}}
The span is only effective to the extent that
the reverse gear ratio
matches that of 1st gear
see also Standard R:1 Digression
is usually longer than 1st gear the effective span is therefore of central importance for describing the suitability of a transmission because in these cases, the nominal spread conveys a misleading picture which is only unproblematic for vehicles with high specific power Market participants
Manufacturers naturally have no interest in specifying the effective span Users have not yet formulated the practical benefits that the effective span has for them The effective span has not yet played a role in research and teaching Contrary to its significance
the effective span has therefore not yet been able to establish itself
either in theory or in practice. End of digression ^ Ratio Span's Center
(
i
1
i
n
)
1
2
{\displaystyle (i_{1}i_{n})^{\frac {1}{2}}}
The center indicates the speed level of the transmission
Together with the final drive ratio
it gives the shaft speed level of the vehicle ^ Average Gear Step
(
ω
2
;
n
ω
2
;
1
)
1
n
−
1
=
(
i
1
i
n
)
1
n
−
1
{\displaystyle \left({\frac {\omega _{2;n}}{\omega _{2;1}}}\right)^{\frac {1}{n-1}}=\left({\frac {i_{1}}{i_{n}}}\right)^{\frac {1}{n-1}}}
There are
n
−
1
{\displaystyle n-1}
n
{\displaystyle n}
with decreasing step width
the gears connect better to each other
shifting comfort increases ^ Sun 1: sun gear of gearset 1
^ Ring 1: ring gear of gearset 1
^ Sun 2: sun gear of gearset 2
^ Ring 2: ring gear of gearset 2
^ a b c d e f g Standard 50:50
With steadily decreasing gear steps (yellow highlighted line Step )
and a particularly large step from 1st to 2nd gear
the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger
and the upper half of the gear steps (between the large gears; rounded up, here the last 2) is always smaller
than the average gear step (cell highlighted yellow two rows above on the far right)lower half: smaller gear steps are a waste of possible ratios (red bold)
upper half: larger gear steps are unsatisfactory (red bold) ^ Standard R:1
The ideal reverse gear has the same transmission ratio as 1st gear
no impairment when maneuvering
especially when towing a trailer
a torque converter can only partially compensate for this deficiency
Plus 11.11 % minus 10 % compared to 1st gear is good
Plus 25 % minus 20 % is acceptable (red) Above this is unsatisfactory (bold) ^ Standard 1:2
With continuously decreasing gear steps (yellow marked line Step )
the largest gear step is the one from 1st to 2nd gear, which
for a good speed connection and
a smooth gear shift
must be as small as possible
A gear ratio of up to 1.6667:1 (5:3) is good
Up to 1.7500:1 (7:4) is acceptable (red) Above is unsatisfactory (bold) ^ a b From large to small gears (from right to left)
^ a b c Standard STEP
Gear steps should
increase: Δ Step (first green highlighted line Δ Step ) is always greater than 1As progressive as possible: Δ Step is always greater than the previous step
Not progressively increasing is acceptable (red) Not increasing is unsatisfactory (bold) ^ Standard SPEED
Shaft speed differences should
increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed ) is always greater than the previous one
1 difference smaller than the previous one is acceptable (red) 2 consecutive ones are a waste of possible ratios (bold) ^ Blocks R1
^ Blocks S2
^ Also BR (brake for reverse gear · German : B remse für R ückwärtsgangC1 and R2
^ Couples C1 and R2 with the input (turbine)
^ Couples C1 and R2 with S2
^ Also KR (clutch for reverse gear · German : K upplung für R ückwärtsgangR1 with S2
^ a b Ordinary Noted
For direct determination of the gear ratio ^ a b Elementary Noted
Alternative representation for determining the transmission ratio
Contains only operands
With simple fractions of both central gears of a planetary gearset
Or with the value 1
As a basis
For reliable
And traceable
Determination of the torque conversion ratio and efficiency
Layout
The Mercedes-Benz 600 , unveiled in September 1963 at the International Motor Show in Frankfurt, it went into production in September 1964 and was the first post-war "Grand Mercedes" , powered by the Mercedes-Benz M100 engine . This made a gearbox for the highest demands of luxury vehicles necessary. The design of the gearbox in the range was out of the question from the outset. The introduction of the 600 was therefore taken as an opportunity to develop a completely new design for the automatic transmission.
Models
1964: K4B 050
The first model with this new layout was the K4B 050 . Beside the new layout the number of pinions is doubled from 3 to 6 to handle the much higher torque of the big block V8 engine .
1967: K4C 025
After the satisfactory experience with the new design, it was adopted in 1967 for the new core model K4C 025 (Type 722.2) of the first automatic transmission series from Mercedes-Benz. With the small block V8 engine M 116 , the K4A 040 (Type 722.2) was launched as a reinforced version of the same design.
1969: K4A 040
With the introduction of the V8 cylinder engines of the M 116 series with a displacement of 3.5 liters, the automatic transmission range was expanded to include the K4A 040 model, which is a reinforced version of the K4C 025 with the same gear ratios to accommodate the increased torque.
1972: W4B 025
When the torque converter technique was fully established, the fluid coupling was replaced by a torque converter for the smaller engines, which leads to the W4B 025 (type 722.1).[ 4] L4 , L5 and L6 engines due to its lower torque output. In normal situations, it rests stationary in 2nd gear, but it will use 1st gear when the vehicle starts moving and throttle is applied[ 6]
Variants For Commercial Cars
The W4A 018 (type 720.1) was derived from the W4B 025 (type 722.1) for light-duty trucks and vans up to 5,600 kg (12,350 lb ) and off-road vehicles ,[ B] [ C] W4B 035 from the W4B 025 (type 722.1) and K4A 040 (type 722.2) for medium-duty trucks up to 13,000 kg (28,660 lb ).[ D] [ E]
Specifications
For this second 4-speed models[ a] [ b] [ 4]
Gear Ratio Analysis[ c]
In-Depth Analysis[ d] [ e] [ f]
Planetary Gearset: Teeth[ g]
Count
Nomi-[ h] [ i]
Cen-[ j]
Simpson
Simple
Avg.[ k]
Model
Version
S1 [ l] 1 [ m]
S2 [ n] 2 [ o]
S3 [ p] 3 [ q]
Brakes
Ratio
Gear[ r]
Gear
R
1
2
3
4
Gear[ d]
i
R
{\displaystyle {i_{R}}}
[ d]
i
1
{\displaystyle {i_{1}}}
[ d]
i
2
{\displaystyle {i_{2}}}
[ d]
i
3
{\displaystyle {i_{3}}}
[ d]
i
4
{\displaystyle {i_{4}}}
[ d]
Step[ r]
−
i
R
i
1
{\displaystyle -{\frac {i_{R}}{i_{1}}}}
[ s]
i
1
i
1
{\displaystyle {\frac {i_{1}}{i_{1}}}}
i
1
i
2
{\displaystyle {\frac {i_{1}}{i_{2}}}}
[ t]
i
2
i
3
{\displaystyle {\frac {i_{2}}{i_{3}}}}
i
3
i
4
{\displaystyle {\frac {i_{3}}{i_{4}}}}
Δ Step[ u] [ v]
i
1
i
2
:
i
2
i
3
{\displaystyle {\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}}
i
2
i
3
:
i
3
i
4
{\displaystyle {\tfrac {i_{2}}{i_{3}}}:{\tfrac {i_{3}}{i_{4}}}}
Shaft
i
1
i
R
{\displaystyle {\frac {i_{1}}{i_{R}}}}
i
1
i
1
{\displaystyle {\frac {i_{1}}{i_{1}}}}
i
1
i
2
{\displaystyle {\frac {i_{1}}{i_{2}}}}
i
1
i
3
{\displaystyle {\frac {i_{1}}{i_{3}}}}
i
1
i
4
{\displaystyle {\frac {i_{1}}{i_{4}}}}
Δ Shaft[ w]
0
−
i
1
i
R
{\displaystyle 0-{\tfrac {i_{1}}{i_{R}}}}
i
1
i
1
−
0
{\displaystyle {\tfrac {i_{1}}{i_{1}}}-0}
i
1
i
2
−
i
1
i
1
{\displaystyle {\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}}
i
1
i
3
−
i
1
i
2
{\displaystyle {\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}}
i
1
i
4
−
i
1
i
3
{\displaystyle {\tfrac {i_{1}}{i_{4}}}-{\tfrac {i_{1}}{i_{3}}}}
Torque[ e]
μ
R
{\displaystyle \mu _{R}}
[ e]
μ
1
{\displaystyle \mu _{1}}
[ e]
μ
2
{\displaystyle \mu _{2}}
[ e]
μ
3
{\displaystyle \mu _{3}}
[ e]
μ
4
{\displaystyle \mu _{4}}
[ e]
Efficiency
η
n
{\displaystyle \eta _{n}}
[ f]
μ
R
i
R
{\displaystyle {\frac {\mu _{R}}{i_{R}}}}
[ f]
μ
1
i
1
{\displaystyle {\frac {\mu _{1}}{i_{1}}}}
[ f]
μ
2
i
2
{\displaystyle {\frac {\mu _{2}}{i_{2}}}}
[ f]
μ
3
i
3
{\displaystyle {\frac {\mu _{3}}{i_{3}}}}
[ f]
μ
4
i
4
{\displaystyle {\frac {\mu _{4}}{i_{4}}}}
[ f]
K4B 050[ x]
51 kp⋅m (500 N⋅m ; 369 lb⋅ft )
50
44
44
3
3.9789
1.9947
1.5846[ r]
Gear
R
1
2
3
4
Gear[ d]
−4.1455
−
228
55
{\displaystyle -{\tfrac {228}{55}}}
3.9789
378
95
{\displaystyle {\tfrac {378}{95}}}
2.4589
1
,
168
475
{\displaystyle {\tfrac {1,168}{475}}}
1.5789 [ v] 1.0000
1
1
{\displaystyle {\tfrac {1}{1}}}
Step
1.0418
1.0000
1.6182
1.5573 1.5789
Δ Step[ u]
1.0391
0.9863 [ v]
Speed
-0.9598
1.0000
1.6182
2.5200
3.9789
Δ Speed
0.9598
1.0000
0.6182
0.9018
1.4589
Torque[ e]
–4.0111
3.9021
2.4125
1.5674
1.0000
Efficiency
η
n
{\displaystyle \eta _{n}}
[ f]
0.9676
0.9807
0.9811
0.9927
1.0000
K4C 025
25 kp⋅m (245 N⋅m ; 181 lb⋅ft )[ B]
44
44
35
3
3.9833
1.9958
1.5852 [ r]
Gear
R
1
2
3
4
Gear[ d]
−5.4779 [ s]
−
2
,
109
385
{\displaystyle -{\tfrac {2,109}{385}}}
3.9833
1
,
665
418
{\displaystyle {\tfrac {1,665}{418}}}
2.3855[ t] [ v]
5
,
439
2
,
280
{\displaystyle {\tfrac {5,439}{2,280}}}
1.4605 [ r]
111
76
{\displaystyle {\tfrac {111}{76}}}
1.0000
1
1
{\displaystyle {\tfrac {1}{1}}}
Step
1.3752 [ s]
1.0000
1.6698 [ t] 1.6333 [ r] 1.4605
Δ Step[ u]
1.0223 [ v] 1.1183
Speed
-0.7271
1.0000
1.6696
2.7273
3.9833
Δ Speed
0.7271
1.0000
0.6696
1.0575
1.2560
Torque[ e]
–5.2949
3.9080
2.3406
1.4513
1.0000
Efficiency
η
n
{\displaystyle \eta _{n}}
[ f]
0.9666
0.9811
0.9812
0.9937
1.0000
K4A 040
40 kp⋅m (392 N⋅m ; 289 lb⋅ft )
44
44
35
3
3.9833
1.9958
1.5852 [ r]
Gear
R
1
2
3
4
Gear[ d]
−5.4779 [ s]
3.9833
2.3855[ t] [ v]
1.4605 [ r] 1.0000
W4B 025
25 kp⋅m (245 N⋅m ; 181 lb⋅ft )[ B]
44
44
35
3
3.9833
1.9958
1.5852 [ r]
Gear
R
1
2
3
4
Gear[ d]
−5.4779 [ s]
3.9833
2.3855[ t] [ v]
1.4605 [ r] 1.0000
W4A 018[ y]
18 kp⋅m (177 N⋅m ; 130 lb⋅ft )
46
46
37
3
4.0060
2.0015
1.5882 [ r]
Gear
R
1
2
3
4
Gear[ d]
−5.4994 [ s]
−
4
,
680
851
{\displaystyle -{\tfrac {4,680}{851}}}
4.0060
7
,
371
1840
{\displaystyle {\tfrac {7,371}{1840}}}
2.3911[ t] [ v]
1
,
339
560
{\displaystyle {\tfrac {1,339}{560}}}
1.4625 [ r]
117
80
{\displaystyle {\tfrac {117}{80}}}
1.0000
1
1
{\displaystyle {\tfrac {1}{1}}}
Step
1.3728 [ s]
1.0000
1.6754 [ t] 1.6349 [ r] 1.4625
Δ Step[ u]
1.0248 [ v] 1.1179
Speed
-0.7284
1.0000
1.6754
2.7391
4.0060
Δ Speed
0.7284
1.0000
0.6754
1.0637
1.2668
Torque[ e]
–5.3157
3.9301
2.3459
1.4533
1.0000
Efficiency
η
n
{\displaystyle \eta _{n}}
[ f]
0.9666
0.9811
0.9811
0.9937
1.0000
W4B 035[ z]
35 kp⋅m (343 N⋅m ; 253 lb⋅ft )
42
42
36
3
4.1758
2.0435
1.6103 [ r]
Gear
R
1
2
3
4
Gear[ d]
−5.8810 [ s]
−
2
,
223
378
{\displaystyle -{\tfrac {2,223}{378}}}
4.1758
3
,
420
819
{\displaystyle {\tfrac {3,420}{819}}}
2.4115[ t] [ v]
627
260
{\displaystyle {\tfrac {627}{260}}}
1.4615 [ r]
57
39
{\displaystyle {\tfrac {57}{39}}}
1.0000
1
1
{\displaystyle {\tfrac {1}{1}}}
Step
1.4083 [ s]
1.0000
1.7360 [ t] 1.6500 [ r] 1.4615
Δ Step[ u]
1.0495 [ v] 1.1289
Speed
-0.7101
1.0000
1.7316
2.8571
4.1758
Δ Speed
0.7101
1.0000
0.7316
1.1255
1.3187
Torque[ e]
–5.6845
4.0955
2.3653
1.4523
1.0000
Efficiency
η
n
{\displaystyle \eta _{n}}
[ f]
0.9666
0.9808
0.9808
0.9937
1.0000
Actuated Shift Elements
Brake B1[ aa]
❶
Brake B2[ ab]
❶
❶
❶
Brake B3[ ac]
❶
Clutch K1[ ad]
❶
❶
Clutch K2[ ae]
❶
❶
❶
Geometric Ratios: Speed Conversion
Gear[ d] [ af] [ ag]
i
R
=
−
R
1
(
S
3
+
R
3
)
S
1
S
3
{\displaystyle i_{R}=-{\frac {R_{1}(S_{3}+R_{3})}{S_{1}S_{3}}}}
i
1
=
(
S
1
+
R
1
)
(
S
3
+
R
3
)
S
1
R
3
{\displaystyle i_{1}={\frac {(S_{1}+R_{1})(S_{3}+R_{3})}{S_{1}R_{3}}}}
i
R
=
−
R
1
S
1
(
1
+
R
3
S
3
)
{\displaystyle i_{R}=-{\tfrac {R_{1}}{S_{1}}}\left(1+{\tfrac {R_{3}}{S_{3}}}\right)}
i
1
=
(
1
+
R
1
S
1
)
(
1
+
S
3
R
3
)
{\displaystyle i_{1}=\left(1+{\tfrac {R_{1}}{S_{1}}}\right)\left(1+{\tfrac {S_{3}}{R_{3}}}\right)}
Gear[ d] [ af] [ ag]
i
2
=
(
S
1
(
S
2
+
R
2
)
+
R
1
S
2
)
(
S
3
+
R
3
)
S
1
(
S
2
+
R
2
)
R
3
{\displaystyle i_{2}={\frac {(S_{1}(S_{2}+R_{2})+R_{1}S_{2})(S_{3}+R_{3})}{S_{1}(S_{2}+R_{2})R_{3}}}}
i
3
=
S
3
+
R
3
R
3
{\displaystyle i_{3}={\frac {S_{3}+R_{3}}{R_{3}}}}
i
2
=
(
1
+
R
1
S
1
1
+
R
2
S
2
)
(
1
+
S
3
R
3
)
{\displaystyle i_{2}=\left(1+{\tfrac {\tfrac {R_{1}}{S_{1}}}{1+{\tfrac {R_{2}}{S_{2}}}}}\right)\left(1+{\tfrac {S_{3}}{R_{3}}}\right)}
i
3
=
1
+
S
3
R
3
{\displaystyle i_{3}=1+{\tfrac {S_{3}}{R_{3}}}}
i
4
=
1
1
{\displaystyle i_{4}={\frac {1}{1}}}
Kinetic Ratios: Torque Conversion
Torque[ e]
μ
R
=
−
R
1
S
1
η
0
(
1
+
R
3
S
3
η
0
)
{\displaystyle \mu _{R}=-{\tfrac {R_{1}}{S_{1}}}\eta _{0}\left(1+{\tfrac {R_{3}}{S_{3}}}\eta _{0}\right)}
μ
1
=
(
1
+
R
1
S
1
η
0
)
(
1
+
S
3
R
3
η
0
)
{\displaystyle \mu _{1}=\left(1+{\tfrac {R_{1}}{S_{1}}}\eta _{0}\right)\left(1+{\tfrac {S_{3}}{R_{3}}}\eta _{0}\right)}
Torque[ e]
μ
2
=
(
1
+
R
1
S
1
η
0
1
+
R
2
S
2
⋅
1
η
0
)
(
1
+
S
3
R
3
η
0
)
{\displaystyle \mu _{2}=\left(1+{\tfrac {{\tfrac {R_{1}}{S_{1}}}\eta _{0}}{1+{\tfrac {R_{2}}{S_{2}}}\cdot {\tfrac {1}{\eta _{0}}}}}\right)\left(1+{\tfrac {S_{3}}{R_{3}}}\eta _{0}\right)}
μ
3
=
1
+
S
3
R
3
η
0
{\displaystyle \mu _{3}=1+{\tfrac {S_{3}}{R_{3}}}\eta _{0}}
μ
4
=
1
1
{\displaystyle \mu _{4}={\frac {1}{1}}}
^ plus 1 reverse gear
^ 3 simple planetary gearsets , 3 brakes, 2 clutches
^ Revised 14 January 2026Nomenclature
S
n
=
{\displaystyle S_{n}=}
R
n
=
{\displaystyle R_{n}=}
C
n
=
{\displaystyle \color {gray}{C_{n}=}}
carrier or planetary gear carrier (not needed)
s
n
=
{\displaystyle s_{n}=}
r
n
=
{\displaystyle r_{n}=}
c
n
=
{\displaystyle c_{n}=}
n
=
{\displaystyle n=}
i
n
=
{\displaystyle i_{n}=}
ω
1
;
n
=
ω
t
=
{\displaystyle \omega _{1;n}=\omega _{t}=}
ω
2
;
n
=
{\displaystyle \omega _{2;n}=}
T
1
;
n
=
T
t
=
{\displaystyle T_{1;n}=T_{t}=}
T
2
;
n
=
{\displaystyle T_{2;n}=}
μ
n
=
{\displaystyle \mu _{n}=}
η
n
=
{\displaystyle \eta _{n}=}
i
0
=
{\displaystyle i_{0}=}
η
0
=
{\displaystyle \eta _{0}=}
^ a b c d e f g h i j k l m n o Gear Ratio (Transmission Ratio)
i
n
{\displaystyle i_{n}}
The gear ratio
i
n
{\displaystyle i_{n}}
is the ratio of
input shaft speed
ω
1
;
n
{\displaystyle \omega _{1;n}}
to output shaft speed
ω
2
;
n
{\displaystyle \omega _{2;n}}
and therefore corresponds to the reciprocal of the shaft speeds
i
n
=
1
ω
2
;
n
ω
1
;
n
=
ω
1
;
n
ω
2
;
n
=
ω
t
ω
2
;
n
{\displaystyle i_{n}={\frac {1}{\frac {\omega _{2;n}}{\omega _{1;n}}}}={\frac {\omega _{1;n}}{\omega _{2;n}}}={\frac {\omega _{t}}{\omega _{2;n}}}}
^ a b c d e f g h i j k l m Torque Ratio (Torque Conversion Ratio)
μ
n
{\displaystyle \mu _{n}}
The torque ratio
μ
n
{\displaystyle \mu _{n}}
is the ratio of
output torque
T
2
;
n
{\displaystyle T_{2;n}}
to input torque
T
1
;
n
{\displaystyle T_{1;n}}
minus efficiency losses
and therefore corresponds (apart from the efficiency losses) to the reciprocal of the shaft speeds too
μ
n
=
i
n
η
n
;
η
0
=
ω
1
;
n
η
n
;
η
0
ω
2
;
n
=
T
2
;
n
η
n
;
η
0
T
1
;
n
{\displaystyle \mu _{n}=i_{n}\eta _{n;\eta _{0}}={\frac {\omega _{1;n}\eta _{n;\eta _{0}}}{\omega _{2;n}}}={\frac {T_{2;n}\eta _{n;\eta _{0}}}{T_{1;n}}}}
whereby
η
n
;
η
0
{\displaystyle \eta _{n;\eta _{0}}}
0
≤
η
n
;
η
0
≤
1
{\displaystyle 0\leq \eta _{n;\eta _{0}}\leq 1}
^ a b c d e f g h i j k Efficiency
The efficiency
η
n
{\displaystyle \eta _{n}}
from the torque ratio
in relation to the gear ratio (transmission ratio)
η
n
=
μ
n
i
n
{\displaystyle \eta _{n}={\frac {\mu _{n}}{i_{n}}}}
Power loss for single meshing gears
is in the range of 1 % to 1.5 %
helical gear pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range
spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range Corridor for torque ratio and efficiency
in planetary gearsets, the stationary gear ratio
i
0
{\displaystyle i_{0}}
is formed via the planetary gears and thus by two meshes
for reasons of simplification, the efficiency for both meshes together is commonly specified there
the efficiencies
η
0
{\displaystyle \eta _{0}}
stationary ratio
i
0
{\displaystyle i_{0}}
of
η
0
=
0.9800
{\displaystyle \eta _{0}=0.9800}
and
η
0
=
0.9700
{\displaystyle \eta _{0}=0.9700}
for both interventions together
The corresponding efficiency
for single-meshing gear pairs is
η
0
1
2
{\displaystyle {\eta _{0}}^{\tfrac {1}{2}}}
at
0.9800
1
2
=
0.98995
{\displaystyle 0.9800^{\tfrac {1}{2}}=0.98995}
and
0.9700
1
2
=
0.98489
{\displaystyle 0.9700^{\tfrac {1}{2}}=0.98489}
^ Layout
Input and output are on opposite sides
Planetary gearset 1 is on the input (turbine) side
Input (turbine) shaft is S1
Output shaft is C3 ^ Total Ratio Span (Total Gear/Transmission Ratio) Nominal
ω
2
;
n
ω
2
;
1
=
ω
2
;
n
ω
2
;
1
ω
2
;
n
ω
2
;
1
ω
2
;
1
ω
2
;
n
=
1
ω
2
;
1
1
ω
2
;
n
=
ω
t
ω
2
;
1
ω
t
ω
2
;
n
=
i
1
i
n
{\displaystyle {\frac {\omega _{2;n}}{\omega _{2;1}}}={\frac {\frac {\omega _{2;n}}{\omega _{2;1}\omega _{2;n}}}{\frac {\omega _{2;1}}{\omega _{2;1}\omega _{2;n}}}}={\frac {\frac {1}{\omega _{2;1}}}{\frac {1}{\omega _{2;n}}}}={\frac {\frac {\omega _{t}}{\omega _{2;1}}}{\frac {\omega _{t}}{\omega _{2;n}}}}={\frac {i_{1}}{i_{n}}}}
A wider span enables the
downspeeding when driving outside the city limits
increase the climbing ability
when driving over mountain passes or off-road
or when towing a trailer ^ Total Ratio Span (Total Gear Ratio/Total Transmission Ratio) Effective
ω
2
;
n
m
a
x
(
ω
2
;
1
;
|
ω
2
;
R
|
)
=
m
i
n
(
i
1
;
|
i
R
|
)
i
n
{\displaystyle {\frac {\omega _{2;n}}{max(\omega _{2;1};|\omega _{2;R}|)}}={\frac {min(i_{1};|i_{R}|)}{i_{n}}}}
The span is only effective to the extent that
the reverse gear ratio
matches that of 1st gear
see also Standard R:1 Digression
is usually longer than 1st gear the effective span is therefore of central importance for describing the suitability of a transmission because in these cases, the nominal spread conveys a misleading picture which is only unproblematic for vehicles with high specific power Market participants
Manufacturers naturally have no interest in specifying the effective span Users have not yet formulated the practical benefits that the effective span has for them The effective span has not yet played a role in research and teaching Contrary to its significance
the effective span has therefore not yet been able to establish itself
either in theory or in practice. End of digression ^ Ratio Span's Center
(
i
1
i
n
)
1
2
{\displaystyle (i_{1}i_{n})^{\frac {1}{2}}}
The center indicates the speed level of the transmission
Together with the final drive ratio
it gives the shaft speed level of the vehicle ^ Average Gear Step
(
ω
2
;
n
ω
2
;
1
)
1
n
−
1
=
(
i
1
i
n
)
1
n
−
1
{\displaystyle \left({\frac {\omega _{2;n}}{\omega _{2;1}}}\right)^{\frac {1}{n-1}}=\left({\frac {i_{1}}{i_{n}}}\right)^{\frac {1}{n-1}}}
There are
n
−
1
{\displaystyle n-1}
n
{\displaystyle n}
with decreasing step width
the gears connect better to each other
shifting comfort increases ^ Sun 1: sun gear of gearset 1
^ Ring 1: ring gear of gearset 1
^ Sun 2: sun gear of gearset 2
^ Ring 2: ring gear of gearset 2
^ Sun 3: sun gear of gearset 3
^ Ring 3: ring gear of gearset 3
^ a b c d e f g h i j k l m n o p Standard 50:50
With steadily decreasing gear steps (yellow highlighted line Step )
and a particularly large step from 1st to 2nd gear
the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger
and the upper half of the gear steps (between the large gears; rounded up, here the last 2) is always smaller
than the average gear step (cell highlighted yellow two rows above on the far right)lower half: smaller gear steps are a waste of possible ratios (red bold)
upper half: larger gear steps are unsatisfactory (red bold) ^ a b c d e f g h i Standard R:1
The ideal reverse gear has the same transmission ratio as 1st gear
no impairment when maneuvering
especially when towing a trailer
a torque converter can only partially compensate for this deficiency
Plus 11.11 % minus 10 % compared to 1st gear is good
Plus 25 % minus 20 % is acceptable (red) Above this is unsatisfactory (bold) ^ a b c d e f g h i Standard 1:2
With continuously decreasing gear steps (yellow marked line Step )
the largest gear step is the one from 1st to 2nd gear, which
for a good speed connection and
a smooth gear shift
must be as small as possible
A gear ratio of up to 1.6667:1 (5:3) is good
Up to 1.7500:1 (7:4) is acceptable (red) Above is unsatisfactory (bold) ^ a b c d e From large to small gears (from right to left)
^ a b c d e f g h i j k Standard STEP
Gear steps should
increase: Δ Step (first green highlighted line Δ Step ) is always greater than 1As progressive as possible: Δ Step is always greater than the previous step
Not progressively increasing is acceptable (red) Not increasing is unsatisfactory (bold) ^ Standard SPEED
Shaft speed differences should
increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed ) is always greater than the previous one
1 difference smaller than the previous one is acceptable (red) 2 consecutive ones are a waste of possible ratios (bold) ^ K4B 050: for the 6.3 L engine M 100 of the 600 and 300 SEL 6.3 ^ W4A 018: for light-duty trucks and vans up to 5,600 kg (12,350 lb ) and off-road vehicles [ B] [ C] ^ W4B 035: for medium-duty trucks up to 13,000 kg (28,660 lb )[ D] [ E] ^ Blocks S2
^ Blocks S3
^ Also BR (brake for reverse gear · German : B remse für R ückwärtsgangC1
^ Couples S2 with C2
^ Couples R1 with S3
^ a b Ordinary Noted
For direct determination of the gear ratio ^ a b Elementary Noted
Alternative representation for determining the transmission ratio
Contains only operands
With simple fractions of both central gears of a planetary gearset
Or with the value 1
As a basis
For reliable
And traceable
Determination of the torque conversion ratio and efficiency
Layout
When the torque converter technique was fully established, 3-speed units, the W3A 040 and W3B 050 (type 722.0) is combined with V8 engines , and it uses torque converter instead of fluid coupling .[ 1] [ 4] V8 engines .
First the W3A 040 was released for the all new M117 V8 engine of the W 108 and W 109 in 1971. The second in the series is the W3B 050 , which was released initially for the W 116 450 SE/SEL in 1973. At that time the 4-speed transmission for the 350 SE/SEL was replaced by this 3-speed model. The reinforced W3B 050 reinforced (type 722.003) is the strongest of the series, able to handle the input of the enlarged version of the M 100 , the biggest Mercedes-Benz engine in post-war history,[ 7] W 116 450 SEL 6.9 .
Specifications
For the 3-speed models[ a] [ b] direct competitor .
Gear Ratio Analysis[ c]
In-Depth Analysis[ d] [ e] [ f]
Planetary Gearset: Teeth[ g]
Count
Nomi-[ h] [ i]
Cen-[ j]
Simple
Avg.[ k]
Model
Version
S1 [ l] 1 [ m]
S2 [ n] 2 [ o]
Brakes
Ratio
Gear[ p]
Gear
R
1
2
3
Gear[ d]
i
R
{\displaystyle {i_{R}}}
[ d]
i
1
{\displaystyle {i_{1}}}
[ d]
i
2
{\displaystyle {i_{2}}}
[ d]
i
3
{\displaystyle {i_{3}}}
[ d]
Step[ p]
−
i
R
i
1
{\displaystyle -{\frac {i_{R}}{i_{1}}}}
[ q]
i
1
i
1
{\displaystyle {\frac {i_{1}}{i_{1}}}}
i
1
i
2
{\displaystyle {\frac {i_{1}}{i_{2}}}}
[ r]
i
2
i
3
{\displaystyle {\frac {i_{2}}{i_{3}}}}
Δ Step[ s] [ t]
i
1
i
2
:
i
2
i
3
{\displaystyle {\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}}
Shaft
i
1
i
R
{\displaystyle {\frac {i_{1}}{i_{R}}}}
i
1
i
1
{\displaystyle {\frac {i_{1}}{i_{1}}}}
i
1
i
2
{\displaystyle {\frac {i_{1}}{i_{2}}}}
i
1
i
3
{\displaystyle {\frac {i_{1}}{i_{3}}}}
Δ Shaft[ u]
0
−
i
1
i
R
{\displaystyle 0-{\tfrac {i_{1}}{i_{R}}}}
i
1
i
1
−
0
{\displaystyle {\tfrac {i_{1}}{i_{1}}}-0}
i
1
i
2
−
i
1
i
1
{\displaystyle {\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}}
i
1
i
3
−
i
1
i
2
{\displaystyle {\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}}
Torque[ e]
μ
R
{\displaystyle \mu _{R}}
[ e]
μ
1
{\displaystyle \mu _{1}}
[ e]
μ
2
{\displaystyle \mu _{2}}
[ e]
μ
3
{\displaystyle \mu _{3}}
[ e]
Efficiency
η
n
{\displaystyle \eta _{n}}
[ f]
μ
R
i
R
{\displaystyle {\frac {\mu _{R}}{i_{R}}}}
[ f]
μ
1
i
1
{\displaystyle {\frac {\mu _{1}}{i_{1}}}}
[ f]
μ
2
i
2
{\displaystyle {\frac {\mu _{2}}{i_{2}}}}
[ f]
μ
3
i
3
{\displaystyle {\frac {\mu _{3}}{i_{3}}}}
[ f]
W3A 040
40 kp⋅m (392 N⋅m ; 289 lb⋅ft )[ F]
44
35
3
2.30611.8361 [ i] [ q]
1.5186
1.5186[ p]
Gear
R
1
2
3
Gear[ d]
−1.8361 [ q] [ i]
−
1
,
221
665
{\displaystyle -{\tfrac {1,221}{665}}}
2.3061
1
,
665
722
{\displaystyle {\tfrac {1,665}{722}}}
1.4605
63
25
{\displaystyle {\tfrac {63}{25}}}
1.0000
1
1
{\displaystyle {\tfrac {1}{1}}}
Step
0.7962 [ q]
1.0000
1.5789
1.4605
Δ Step[ s]
1.0811
Speed
-1.2560
1.0000
1.5789
2.3061
Δ Speed
1.2560
1.0000
0.5789
0.9411
Torque[ e]
–1.7747
2.2747
1.4513
1.0000
Efficiency
η
n
{\displaystyle \eta _{n}}
[ f]
0.9666
0.9864
0.9937
1.0000
W3A 050
50 kp⋅m (490 N⋅m ; 362 lb⋅ft )[ F]
44
35
3
2.30611.8361 [ i] [ q]
1.5186
1.5186[ p]
Gear
R
1
2
3
Gear[ d]
−1.8361 [ q] [ i]
2.3061
1.4605
1.0000
W3A 050[ v]
56 kp⋅m (549 N⋅m ; 405 lb⋅ft )[ F]
44
35
3
2.30611.8361 [ i] [ q]
1.5186
1.5186[ p]
Gear
R
1
2
3
Gear[ d]
−1.8361 [ q] [ i]
2.3061
1.4605
1.0000
Actuated Shift Elements
Brake B1[ w]
❶
Brake B2[ x]
❶
❶
Brake B3[ y]
❶
Clutch K1[ z]
❶
❶
Clutch K2[ aa]
❶
❶
Geometric Ratios: Speed Conversion
Gear[ d] [ ab] [ ac]
i
R
=
−
S
1
(
S
2
+
R
2
)
R
1
S
2
{\displaystyle i_{R}=-{\frac {S_{1}(S_{2}+R_{2})}{R_{1}S_{2}}}}
i
2
=
S
2
+
R
2
R
2
{\displaystyle i_{2}={\frac {S_{2}+R_{2}}{R_{2}}}}
i
R
=
−
S
1
R
1
(
1
+
R
2
S
2
)
{\displaystyle i_{R}=-{\tfrac {S_{1}}{R_{1}}}(1+{\tfrac {R_{2}}{S_{2}}})}
i
2
=
1
+
S
2
R
2
{\displaystyle i_{2}=1+{\tfrac {S_{2}}{R_{2}}}}
Gear[ d] [ ab] [ ac]
i
1
=
(
S
1
+
R
1
)
(
S
2
+
R
2
)
R
1
R
2
{\displaystyle i_{1}={\frac {(S_{1}+R_{1})(S_{2}+R_{2})}{R_{1}R_{2}}}}
i
3
=
1
1
{\displaystyle i_{3}={\frac {1}{1}}}
i
1
=
(
1
+
S
1
R
1
)
(
1
+
S
2
R
2
)
{\displaystyle i_{1}=\left(1+{\tfrac {S_{1}}{R_{1}}}\right)\left(1+{\tfrac {S_{2}}{R_{2}}}\right)}
i
3
=
1
1
{\displaystyle i_{3}={\frac {1}{1}}}
Kinetic Ratios: Torque Conversion
Torque[ e]
m
u
R
=
−
S
1
R
1
η
0
(
1
+
R
2
S
2
η
0
)
{\displaystyle mu_{R}=-{\tfrac {S_{1}}{R_{1}}}\eta _{0}(1+{\tfrac {R_{2}}{S_{2}}}\eta _{0})}
m
u
2
=
1
+
S
2
R
2
η
0
{\displaystyle mu_{2}=1+{\tfrac {S_{2}}{R_{2}}}\eta _{0}}
Torque[ e]
m
u
1
=
(
1
+
S
1
R
1
η
0
)
(
1
+
S
2
R
2
η
0
)
{\displaystyle mu_{1}=\left(1+{\tfrac {S_{1}}{R_{1}}}\eta _{0}\right)\left(1+{\tfrac {S_{2}}{R_{2}}}\eta _{0}\right)}
m
u
3
=
1
1
{\displaystyle mu_{3}={\frac {1}{1}}}
^ plus 1 reverse gear
^ 2 simple planetary gearsets ,[ 4] clutches
^ Revised 14 January 2026Nomenclature
S
n
=
{\displaystyle S_{n}=}
R
n
=
{\displaystyle R_{n}=}
C
n
=
{\displaystyle \color {gray}{C_{n}=}}
carrier or planetary gear carrier (not needed)
s
n
=
{\displaystyle s_{n}=}
r
n
=
{\displaystyle r_{n}=}
c
n
=
{\displaystyle c_{n}=}
n
=
{\displaystyle n=}
i
n
=
{\displaystyle i_{n}=}
ω
1
;
n
=
ω
t
=
{\displaystyle \omega _{1;n}=\omega _{t}=}
ω
2
;
n
=
{\displaystyle \omega _{2;n}=}
T
1
;
n
=
T
t
=
{\displaystyle T_{1;n}=T_{t}=}
T
2
;
n
=
{\displaystyle T_{2;n}=}
μ
n
=
{\displaystyle \mu _{n}=}
η
n
=
{\displaystyle \eta _{n}=}
i
0
=
{\displaystyle i_{0}=}
η
0
=
{\displaystyle \eta _{0}=}
^ a b c d e f g h i j k Gear Ratio (Transmission Ratio)
i
n
{\displaystyle i_{n}}
The gear ratio
i
n
{\displaystyle i_{n}}
is the ratio of
input shaft speed
ω
1
;
n
{\displaystyle \omega _{1;n}}
to output shaft speed
ω
2
;
n
{\displaystyle \omega _{2;n}}
and therefore corresponds to the reciprocal of the shaft speeds
i
n
=
1
ω
2
;
n
ω
1
;
n
=
ω
1
;
n
ω
2
;
n
=
ω
t
ω
2
;
n
{\displaystyle i_{n}={\frac {1}{\frac {\omega _{2;n}}{\omega _{1;n}}}}={\frac {\omega _{1;n}}{\omega _{2;n}}}={\frac {\omega _{t}}{\omega _{2;n}}}}
^ a b c d e f g h i Torque Ratio (Torque Conversion Ratio)
μ
n
{\displaystyle \mu _{n}}
The torque ratio
μ
n
{\displaystyle \mu _{n}}
is the ratio of
output torque
T
2
;
n
{\displaystyle T_{2;n}}
to input torque
T
1
;
n
{\displaystyle T_{1;n}}
minus efficiency losses
and therefore corresponds (apart from the efficiency losses) to the reciprocal of the shaft speeds too
μ
n
=
i
n
η
n
;
η
0
=
ω
1
;
n
η
n
;
η
0
ω
2
;
n
=
T
2
;
n
η
n
;
η
0
T
1
;
n
{\displaystyle \mu _{n}=i_{n}\eta _{n;\eta _{0}}={\frac {\omega _{1;n}\eta _{n;\eta _{0}}}{\omega _{2;n}}}={\frac {T_{2;n}\eta _{n;\eta _{0}}}{T_{1;n}}}}
whereby
η
n
;
η
0
{\displaystyle \eta _{n;\eta _{0}}}
0
≤
η
n
;
η
0
≤
1
{\displaystyle 0\leq \eta _{n;\eta _{0}}\leq 1}
^ a b c d e f g Efficiency
The efficiency
η
n
{\displaystyle \eta _{n}}
from the torque ratio
in relation to the gear ratio (transmission ratio)
η
n
=
μ
n
i
n
{\displaystyle \eta _{n}={\frac {\mu _{n}}{i_{n}}}}
Power loss for single meshing gears
is in the range of 1 % to 1.5 %
helical gear pairs, which are used to reduce noise in passenger cars, are in the upper part of the loss range
spur gear pairs, which are limited to commercial vehicles due to their poorer noise comfort, are in the lower part of the loss range Corridor for torque ratio and efficiency
in planetary gearsets, the stationary gear ratio
i
0
{\displaystyle i_{0}}
is formed via the planetary gears and thus by two meshes
for reasons of simplification, the efficiency for both meshes together is commonly specified there
the efficiencies
η
0
{\displaystyle \eta _{0}}
stationary ratio
i
0
{\displaystyle i_{0}}
of
η
0
=
0.9800
{\displaystyle \eta _{0}=0.9800}
and
η
0
=
0.9700
{\displaystyle \eta _{0}=0.9700}
for both interventions together
The corresponding efficiency
for single-meshing gear pairs is
η
0
1
2
{\displaystyle {\eta _{0}}^{\tfrac {1}{2}}}
at
0.9800
1
2
=
0.98995
{\displaystyle 0.9800^{\tfrac {1}{2}}=0.98995}
and
0.9700
1
2
=
0.98489
{\displaystyle 0.9700^{\tfrac {1}{2}}=0.98489}
^ Layout
Input and output are on opposite sides
Planetary gearset 1 is on the input (turbine) side
Input (turbine) shaft is R1
Output shaft is C2 ^ Total Ratio Span (Total Gear/Transmission Ratio) Nominal
ω
2
;
n
ω
2
;
1
=
ω
2
;
n
ω
2
;
1
ω
2
;
n
ω
2
;
1
ω
2
;
1
ω
2
;
n
=
1
ω
2
;
1
1
ω
2
;
n
=
ω
t
ω
2
;
1
ω
t
ω
2
;
n
=
i
1
i
n
{\displaystyle {\frac {\omega _{2;n}}{\omega _{2;1}}}={\frac {\frac {\omega _{2;n}}{\omega _{2;1}\omega _{2;n}}}{\frac {\omega _{2;1}}{\omega _{2;1}\omega _{2;n}}}}={\frac {\frac {1}{\omega _{2;1}}}{\frac {1}{\omega _{2;n}}}}={\frac {\frac {\omega _{t}}{\omega _{2;1}}}{\frac {\omega _{t}}{\omega _{2;n}}}}={\frac {i_{1}}{i_{n}}}}
A wider span enables the
downspeeding when driving outside the city limits
increase the climbing ability
when driving over mountain passes or off-road
or when towing a trailer ^ a b c d e f g Total Ratio Span (Total Gear Ratio/Total Transmission Ratio) Effective
ω
2
;
n
m
a
x
(
ω
2
;
1
;
|
ω
2
;
R
|
)
=
m
i
n
(
i
1
;
|
i
R
|
)
i
n
{\displaystyle {\frac {\omega _{2;n}}{max(\omega _{2;1};|\omega _{2;R}|)}}={\frac {min(i_{1};|i_{R}|)}{i_{n}}}}
The span is only effective to the extent that
the reverse gear ratio
matches that of 1st gear
see also Standard R:1 Digression
is usually longer than 1st gear the effective span is therefore of central importance for describing the suitability of a transmission because in these cases, the nominal spread conveys a misleading picture which is only unproblematic for vehicles with high specific power Market participants
Manufacturers naturally have no interest in specifying the effective span Users have not yet formulated the practical benefits that the effective span has for them The effective span has not yet played a role in research and teaching Contrary to its significance
the effective span has therefore not yet been able to establish itself
either in theory or in practice. End of digression ^ Ratio Span's Center
(
i
1
i
n
)
1
2
{\displaystyle (i_{1}i_{n})^{\frac {1}{2}}}
The center indicates the speed level of the transmission
Together with the final drive ratio
it gives the shaft speed level of the vehicle ^ Average Gear Step
(
ω
2
;
n
ω
2
;
1
)
1
n
−
1
=
(
i
1
i
n
)
1
n
−
1
{\displaystyle \left({\frac {\omega _{2;n}}{\omega _{2;1}}}\right)^{\frac {1}{n-1}}=\left({\frac {i_{1}}{i_{n}}}\right)^{\frac {1}{n-1}}}
There are
n
−
1
{\displaystyle n-1}
n
{\displaystyle n}
with decreasing step width
the gears connect better to each other
shifting comfort increases ^ Sun 1: sun gear of gearset 1
^ Ring 1: ring gear of gearset 1
^ Sun 2: sun gear of gearset 2
^ Ring 2: ring gear of gearset 2
^ a b c d e Standard 50:50
With steadily decreasing gear steps (yellow highlighted line Step )
and a particularly large step from 1st to 2nd gear
the lower half of the gear steps (between the small gears; rounded down, here the first 1) is always larger
and the upper half of the gear steps (between the large gears; rounded up, here the last 1) is always smaller
than the average gear step (cell highlighted yellow two rows above on the far right)lower half: smaller gear steps are a waste of possible ratios (red bold)
upper half: larger gear steps are unsatisfactory (red bold) ^ a b c d e f g h Standard R:1
The ideal reverse gear has the same transmission ratio as 1st gear
no impairment when maneuvering
especially when towing a trailer
a torque converter can only partially compensate for this deficiency
Plus 11.11 % minus 10 % compared to 1st gear is good
Plus 25 % minus 20 % is acceptable (red) Above this is unsatisfactory (bold) ^ Standard 1:2
With continuously decreasing gear steps (yellow marked line Step )
the largest gear step is the one from 1st to 2nd gear, which
for a good speed connection and
a smooth gear shift
must be as small as possible
A gear ratio of up to 1.6667 : 1 (5 : 3) is good
Up to 1.7500 : 1 (7 : 4) is acceptable (red) Above is unsatisfactory (bold) ^ a b From large to small gears (from right to left)
^ Standard STEP
Gear steps should
increase: Δ Step (first green highlighted line Δ Step ) is always greater than 1As progressive as possible: Δ Step is always greater than the previous step
Not progressively increasing is acceptable (red) Not increasing is unsatisfactory (bold) ^ Standard SPEED
Shaft speed differences should
increase: Δ Shaft Speed (second line marked in green Δ (Shaft) Speed ) is always greater than the previous one
1 difference smaller than the previous one is acceptable (red) 2 consecutive ones are a waste of possible ratios (bold) ^ W3A 050 reinforced: for the 6.8 L engine M 100 of the 450 SEL 6.9 ^ Blocks S1
^ Blocks S2
^ Blocks C1
^ Couples S1 with C1
^ Couples S1 with S2
^ a b Ordinary Noted
For direct determination of the gear ratio ^ a b Elementary Noted
Alternative representation for determining the transmission ratio
Contains only operands
With simple fractions of both central gears of a planetary gearset
Or with the value 1
As a basis
For reliable
And traceable
Determination of the torque conversoin ratio and efficiency
Applications
K4A 025
1961–1965 (saloon) · 1961–1968 (coupé/convertible) W 111
1961–1965 (saloon) · 1962–1968 (coupé/convertible) W 112
1961–1968 W 110
1963–1971 W 113
1965–1968 W 108/W 109
K4B 050
K4C 025
W 114/W 115
Chassis code
Car model
Engine code
Transmission
114.015 and 114.615
230.6
180.954
722.203
114.017 and 114.617
230.6 Lang
114.011 and 114.611
250
130.923
722.204
114.023 and 114.623
250 C
114.060 and 114.660
280
110.921
722.202
114.073 and 114.673
280 C
114.062 and 114.662
280 E
110.981
722.200
114.072 and 114.672
280 CE
115.015 and 115.615
200
115.923
722.205
115.010
220
115.920
115.115 and 115.715
200 D
615.913
722.206
115.110 and 115.710
220 D
615.912
115.112
220 D Lang
K4A 040
W 108/W 109
Chassis code
Car model
Engine code
Transmission
Notes
109.057
300 SEL 3.5
3.5 L M 116 V8
722.201
worldwide
108.067
280 SE 3.5
108.068
280 SEL 3.5
R 107/C 107
Chassis code
Car model
Engine code
Transmission
107.043
350 SL
116.982 (D-Jet)
722.201
107.023
350 SLC
W3A 040
W 108/W 109
Chassis code
Car model
Engine code
Transmission
Notes
109.056
300 SEL 4.5
4.5 L M 117 V8
722.000
USA only
108.057
280 SE 4.5
108.058
280 SEL 4.5
R 107/C 107
Chassis code
Car model
Engine code
Transmission
Notes
107.043
350 SL
116.982 (D-Jet)
722.002
107.023
350 SLC
107.044
450 SL
117.982 (D-Jet)
722.004
USA and
107.024
450 SLC
W 116
Chassis code
Car model
Engine code
Transmission
Notes
116.028
350 SE
116.983 (D-Jet)
722.002
116.029
350 SEL
116.032
450 SE
117.983 (D-Jet)
722.004
USA and
116.033
450 SEL
W3B 050
R 107/C 107
Chassis code
Car model
Engine code
Transmission
Notes
107.044
450 SL
117.982 (D-Jet)
722.001
worldwide except
107.024
450 SLC
W 116
Chassis code
Car model
Engine code
Transmission
Notes
116.032
450 SE
117.983 (D-Jet)
722.001
worldwide except
116.033
450 SEL
116.036
450 SEL 6.9
100.985
722.003
722.003[ 8]
W4B 025
R 107/C 107
Chassis code
Car model
Engine code
Transmission
107.042
280 SL
110.982
722.103
107.022
280 SLC
110.982
W 114/W 115
Chassis code
Car model
Engine code
Transmission
114.015 and 114.615
230.6
180.954
722.105
114.017 and 114.617
230.6 Lang
114.011 and 114.611
250
130.923
722.104
114.023 and 114.623
250 C
114.060 and 114.660
280
110.921
722.102
114.073 and 114.673
280 C
114.062 and 114.662
280 E
110.981
722.103
114.072 and 114.672
280 CE
115.015 and 115.615
200
115.923
722.106
115.017
230.4
115.951
722.110
115.115 and 115.715
200 D
615.913
722.107
115.110 and 115.710
220 D
615.912
115.112
220 D Lang
115.117
240 D
616.916
722.108
115.119
240 D Lang
115.114
240 D 3.0
617.910
722.109
W 116
Chassis code
Car model
Engine code
Transmission
Notes
116.020
280 S
110.922
722.100
116.024
280 SE
110.983 (D-Jet)
722.101
116.025
280 SEL
116.120
300 SD
617.950
722.120
USA only
W 123
Chassis code
Car model
Engine code
Transmission
Notes
123.020
200
115.938
722.115
123.220
200
102.920
722.121
123.280
200 T
123.023
230
115.954
722.119
123.083
230 T
123.043
230 C
123.223
230 E
102.980
722.122
123.283
230 TE
123.243
230 CE
123.026
250
123.920
722.113
123.086
250 T
123.028
250 Lang
123.030
280
110.923
722.111
123.050
280 C
123.033
280 E
110.984
722.112
123.093
280 TE
123.053
280 CE
123.120
200 D
615.940
722.116
123.126
220 D
615.941
123.123
240 D
616.912
722.117
123.183
240 TD
123.125
240 D Lang
123.130
300 D
617.912
722.118
123.190
300 TD
123.132
300 D Lang
123.150
300 CD
USA only
See also
Notes
References
^ a b "50 years of automatic transmissions from Mercedes-Benz" .^ a b Johannes Looman · Gear Transmissions · pp. 133 ff · German : Johannes Looman · Zahnradgetriebe · Berlin und Heidelberg 1970 · Print ISBN 978-3-540-04894-7 · S. 133 ff
^ a b c Result And Outlook · commemorative publication for Prof. Dr. Hans-Joachim Foerster on the occasion of leaving as director from active duty at Daimler-Benz AG · November 1982 · German : Ergebnis und Ausblick · Festschrift für Herrn Prof. Dr. Hans-Joachim Förster zum Ausscheiden als Direktor aus dem aktiven Dienst der Daimler-Benz AG · November 1982
^ a b c d e "MB Passenger Car Series 116" (PDF) .^ a b c Hans-Joachim Foerster · Automatic Vehicle Transmissions · German : Hans-Joachim Förster · Automatische Fahrzeuggetriebe · Berlin und Heidelberg 1991 · Print ISBN 978-3-642-84119-4 · eBook ISBN 978-3-642-84118-7
^ "MB Passenger Car Series 116" (PDF) .^ Only surpassed by the Mercedes-Benz 770 , built from 1930 to 1943
^ "MB AUS 1979" (PDF) . 
