Mercedes-Benz first series automatic transmission

From testwiki
Jump to navigation Jump to search

Template:Short description Template:Infobox automobile

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.

This transmission was the first Mercedes-Benz automatic transmission in-house developing.[1] Before this, the company used 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.

Gear RatiosTemplate:Efn
Template:Diagonal split header R 1 2 3 4 Total
Span
Span
Center
Avg.
Step
Compo-
nents
K4A 025 · 1961 Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round 2 Gearsets
3 Brakes
3 Clutches
K4B 050 · 1964 Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round 3
Gearsets
3
Brakes
2
Clutches
K4C 025 · 1967
K4A 040 · 1969
W4B 025 · 1972
Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round
W4A 018 · 1975 Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round
W4B 035 · 1975 Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round
W3A 040 · 1971
W3A 050 · 1973
W3A 050 reinf. · 1975
Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round Template:Round 2 Gearsets
3 Brakes
2 Clutches

Template:Notelist

1961: K4A 025
— 4-Speed Transmission With 2 Planetary Gearsets —

Layout

The K4A 025Template:Efn (without type designation) is the first of the series, launched in April 1961 for the W111 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 modelTemplate:Efn 8 main componentsTemplate:Efn are used. It is the only exemption which uses only 2 planetary gearsets for 4 speeds.

Template:Notelist

Gear Ratios
With Assessment Planetary Gearset:
Teeth SimpleTemplate:Efn
Count TotalTemplate:Efn
CenterTemplate:Efn
Avg.Template:Efn
Model
Type
Version
First Delivery
S1Template:Efn
R1Template:Efn
S2Template:Efn
R2Template:Efn
Brakes
Clutches
Ratio
Span
Gear
StepTemplate:Efn
Gear
Ratio
R
iR
1
i1
2
i2
3
i3
4
i4
StepTemplate:Efn iRi1Template:Efn i1i1 i1i2Template:Efn i2i3 i3i4
Δ StepTemplate:EfnTemplate:Efn i1i2:i2i3 i2i3:i3i4
Shaft
Speed
i1iR i1i1 i1i2 i1i3 i1i4
Δ Shaft
SpeedTemplate:Efn
0i1iR i1i10 i1i2i1i1 i1i3i1i2 i1i4i1i3
K4A 025
N/A
Template:Convert
1961[2][3]
50
76
44
76
3
3
Template:Round
Template:Round
Template:Font colorTemplate:Efn
Gear
Ratio
Template:Round
22855
Template:Round
37895
Template:Font color Template:Font color 1.0000
11
Step 1.0418 1.0000 Template:Font colorTemplate:Efn Template:Font colorTemplate:Efn 1.5789
Δ StepTemplate:Efn Template:Font colorTemplate:Efn 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
Ratio
R & Even
R1(S2+R2)S1S2 S1+R1S1 11
Ratio
Odd
(S1+R1)(S2+R2)S1R2 S2+R2R2
Algebra And Actuated Shift Elements
Brake ATemplate:Efn
Brake BTemplate:Efn
Brake RTemplate:Efn
Clutch DTemplate:Efn
Clutch ETemplate:Efn
Clutch FTemplate:Efn
Template:Notelist

1964: K4B 050 And Follow-Up Products
— 4-Speed Transmissions With 3 Planetary Gearsets —

Layout

The Mercedes-Benz 600 from April 1964, the first post-war "Grand Mercedes", is 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.

The first model with this new layout was the K4B 050 (without type designation). 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.

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 more powerful version of the same design.

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] Used in 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[5] or if L position is selected in gear selector.

The W4A 018 (type 720.1) was derived from the W4B 025 (type 722.1) for vans up to Template:Convert[6] and off road vehicles, the W4B 035 from the W4B 025 (type 722.1) and K4A 040 (type 722.2) for light trucks up to Template:Convert.[7] The main difference is the use of straight-cut planetary gearsets instead of helical-cut ones for better fuel efficiency at the price of lower noise comfort.

Specifications

For this second 4-speed modelsTemplate:Efn 8 main componentsTemplate:Efn are used.[4]

Template:Notelist

Gear Ratios
With Assessment Planetary Gearset: TeethTemplate:Efn Count TotalTemplate:Efn
CenterTemplate:Efn
Avg.Template:Efn
Simpson Simple
Model
Type
Version
First Delivery
S1Template:Efn
R1Template:Efn
S2Template:Efn
R2Template:Efn
S3Template:Efn
R3Template:Efn
Brakes
Clutches
Ratio
Span
Gear
StepTemplate:Efn
Gear
Ratio
R
iR
1
i1
2
i2
3
i3
4
i4
StepTemplate:Efn iRi1Template:Efn i1i1 i1i2Template:Efn i2i3 i3i4
Δ StepTemplate:EfnTemplate:Efn i1i2:i2i3 i2i3:i3i4
Shaft
Speed
i1iR i1i1 i1i2 i1i3 i1i4
Δ Shaft
SpeedTemplate:Efn
0i1iR i1i10 i1i2i1i1 i1i3i1i2 i1i4i1i3
K4B 050
N/A
Template:Convert
1964
50
76
44
76
44
76
3
2
Template:Round
Template:Round
Template:RoundTemplate:Efn
Gear
Ratio
Template:Round
22855
Template:Round
37895
Template:Round
1,168475
Template:Font colorTemplate:Efn 1.0000
11
Step 1.0418 1.0000 1.6182 Template:Font color 1.5789
Δ StepTemplate:Efn 1.0391 Template:Font colorTemplate:Efn
Speed -0.9598 1.0000 1.6182 2.5200 3.9789
Δ Speed 0.9598 1.0000 0.6182 0.9018 1.4589
K4C 025
722.2
Template:Convert
1967[6]
44
76
44
76
35
76
3
2
Template:Round
Template:Round
Template:Font colorTemplate:Efn
Gear
Ratio
Template:Font color Template:Round
1,665418
Template:Font color Template:Font color 1.0000
11
Step Template:Font colorTemplate:Efn 1.0000 Template:Font colorTemplate:Efn Template:Font colorTemplate:Efn 1.4605
Δ StepTemplate:Efn Template:Font colorTemplate:Efn 1.1183
Speed Template:Font color 1.0000 1.6696 2.7273 3.9833
Δ Speed Template:Font color 1.0000 0.6696 1.0575 1.2560
K4A 040
722.2
Template:Convert
1969
44
76
44
76
35
76
3
2
Template:Round
Template:Round
Template:Font colorTemplate:Efn
Ratio Template:Font color Template:Round Template:Font color Template:Font color 1.0000
W4B 025
722.1
Template:Convert
1972[6]
44
76
44
76
35
76
3
2
Template:Round
Template:Round
Template:Font colorTemplate:Efn
Ratio Template:Font color Template:Round Template:Font color Template:Font color 1.0000
W4A 018Template:Efn
720.1
Template:Convert
1975
46
80
46
80
37
80
3
2
Template:Round
Template:Round
Template:Font colorTemplate:Efn
Gear
Ratio
Template:Font color Template:Round
7,3711840
Template:Font color Template:Font color 1.0000
11
Step Template:Font colorTemplate:Efn 1.0000 Template:Font colorTemplate:Efn Template:Font colorTemplate:Efn 1.4625
Δ StepTemplate:Efn Template:Font colorTemplate:Efn 1.1179
Speed Template:Font color 1.0000 1.6754 2.7391 4.0060
Δ Speed Template:Font color 1.0000 0.6754 1.0637 1.2668
W4B 035Template:Efn
N/A
Template:Convert
1975
42
78
42
78
36
78
3
2
Template:Round
Template:Round
Template:Font colorTemplate:Efn
Gear
Ratio
Template:Font color Template:Round
3,420819
Template:Font color Template:Font color 1.0000
11
Step Template:Font colorTemplate:Efn 1.0000 Template:Font colorTemplate:Efn Template:Font colorTemplate:Efn 1.4615
Δ StepTemplate:Efn Template:Font colorTemplate:Efn 1.1289
Speed Template:Font color 1.0000 1.7316 2.8571 4.1758
Δ Speed Template:Font color 1.0000 0.7316 1.1255 1.3187
Ratio
R & Even
R1(S3+R3)S1S3 (S1(S2+R2)+R1S2)(S3+R3)S1(S2+R2)R3 11
Ratio
Odd
i1=(S1+R1)(S3+R3)S1R3 i3=S3+R3R3
Algebra And Actuated Shift Elements
Brake ATemplate:Efn
Brake BTemplate:Efn
Brake RTemplate:Efn
Clutch DTemplate:Efn
Clutch ETemplate:Efn
Template:Notelist

1971: W3A 040 And Follow-Up Products
— 3-Speed Transmissions With 2 Planetary Gearsets —

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] The transmission saves 1 planetary gearset and uses the same housing as the 4-speed versions. The free space therefore is used to reinforce the shift elements (brakes and clutches) to handle the higher torque of the V8 engines.

First the W3A 040 was released for the all new M117 V8 engine of the Mercedes-Benz W108 and W109 in 1971. The second in the series is the W3B 050, which was released initially for the W116 450 SE and SEL in 1973. At that time the 4-speed transmission for the 350 SE and 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 Mercedes-Benz M100 engine, the biggest Mercedes-Benz engine in post-war history,[8] exclusively used in the W116 450 SEL 6.9.

Specifications

For the 3-speed modelsTemplate:Efn 7 main componentsTemplate:Efn are used, which shows economic equivalence with the direct competitor.

Template:Notelist

Gear Ratios
With Assessment Simple Planetary
Gearset: TeethTemplate:Efn
Count TotalTemplate:Efn
CenterTemplate:Efn
Avg.Template:Efn
Model
Type
Version
First Delivery
S1Template:Efn
R1Template:Efn
S2Template:Efn
R2Template:Efn
Brakes
Clutches
Ratio
Span
Gear
StepTemplate:Efn
Gear
Ratio
R
iR
1
i1
2
i2
3
i3
StepTemplate:Efn iRi1Template:Efn i1i1 i1i2Template:Efn i2i3
Δ StepTemplate:EfnTemplate:Efn i1i2:i2i3
Shaft
Speed
i1iR i1i1 i1i2 i1i3
Δ Shaft
SpeedTemplate:Efn
0i1iR i1i10 i1i2i1i1 i1i3i1i2
W4A 040
722.0
Template:Convert
1971[9]
44
76
35
76
3
2
Template:Round
Template:Round
Template:RoundTemplate:Efn
Gear
Ratio
Template:Font color Template:Round
1,665722
Template:Round
6325
1.0000
11
Step Template:Font colorTemplate:Efn 1.0000 1.5789 1.4605
Δ StepTemplate:Efn 1.0811
Speed Template:Font color 1.0000 1.5789 2.3061
Δ Speed Template:Font color 1.0000 0.5789 0.9411
W4A 050
722.0
Template:Convert
1973[9]
44
76
35
76
3
2
Template:Round
Template:Round
Template:RoundTemplate:Efn
Ratio Template:Font color Template:Round Template:Round 1.0000
W4A 050 reinf.
722.0
Template:Convert
1975[9]
44
76
35
76
3
2
Template:Round
Template:Round
Template:RoundTemplate:Efn
Ratio Template:Font color Template:Round Template:Round 1.0000
Ratio S1(S2+R2)R1S2 (S1+R1)(S2+R2)R1R2 S2+R2R2 11
Algebra And Actuated Shift Elements
Brake ATemplate:Efn
Brake BTemplate:Efn
Brake RTemplate:Efn
Clutch DTemplate:Efn
Clutch ETemplate:Efn
Template:Notelist

Applications

K4A 025

W108
W109
W110
W111
W112
W113

K4C 025

K4A 040

W3A 040

W3B 050

W4B 025

See also

Template:Portal

References

Template:Reflist {{#interlanguagelink:de|Mercedes-Benz K4A 025}}

  1. 1.0 1.1 Template:Cite web
  2. Johannes Looman · Zahnradgetriebe · pp. 133 ff · Berlin and Heidelberg 1970 · Print Template:ISBN
  3. 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 (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) · pp. 6 · 20
  4. 4.0 4.1 4.2 Template:Cite web
  5. Template:Cite web
  6. 6.0 6.1 6.2 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 (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) · pp. 7 · 20
  7. 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 (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) · pp. 9 · 22
  8. Only surpassed by the Mercedes-Benz 770, built from 1930 to 1943
  9. 9.0 9.1 9.2 Hans Joachim Foerster · Automatische Fahrzeuggetriebe · p. 452 · Berlin and Heidelberg 1991 · Print Template:ISBN · Online Template:ISBN
  10. Template:Cite web