Mercedes-Benz 9G-Tronic transmission

9G-Tronic is Mercedes-Benz's trademark name for its nine-speed automatic transmission, starting off with the W9A 700 (Wandler-9-Gang-Automatik bis 700 Nm Eingangsdrehmoment; converter-9-gear-automatic with 516 lb-ft maximum input torque; type 725.0) as core model.

9G-Tronic
Overview
ManufacturerDaimler AG
Production2013–present
Body and chassis
Class9-speed longitudinal automatic transmission
Chronology
PredecessorMercedes-Benz 7G-Tronic transmission

Abstract

In all applications this transmission is identified as the New Automatic Gearbox Generation Three, or NAG3. Initially it debuted on the E 350 blueTEC in 2013,[1][2] before launched in the Mercedes-Benz S-Class (W222). It has been expanded to be used in the Mercedes-Benz C-Class (W205) and the sedan and wagon variants of the Mercedes-Benz E-Class (W213). This transmission was later introduced on Mercedes-Benz M-Class (W166) facelift on the GLE 250 d model. V12 engine models continue to use the older Mercedes-Benz 7G-Tronic transmission. By the end of 2018 unsurpassed ratio span among longitudinal automatic transmissions for passenger cars.

It is also fabricated by Jatco for use in Nissan and Infiniti vehicles.[3][4]

Specifications

Basic concept

Technical and economic progress is reflected in 9 forward gears[lower-alpha 1] out of 10 main components,[lower-alpha 2][5] compared to 7 forward gears[lower-alpha 3] out of 11 main components[lower-alpha 4] in the direct predecessor. It is fully electronic controlled. Torque converter lock-up can operate in all 9 forward gears.

Gear ratios

Gear Teeth and Ratios Planetary Gearset: Teeth Count Total Avg.
Model

Type

First Delivery Sun 1

Ring 1

Sun 2

Ring 2

Sun 3

Ring 3

Sun 4

Ring 4

Brakes

Clutches

Ratio

Span

Gear

Step

Gear 1 2 3 4 5 6 7 8 9 R
W9A ALL

725.0

2013[lower-alpha 5][5] 46

98

44

100

36

84

34

86

3

3

9.1495 1.3188
Ratio 5.5032 3.3333 2.3148 1.6611 1.2106 1.0000 0.8651 0.7167 0.60148 - 4.9316
W9A ALL

725.0

2016[lower-alpha 6][6] 46

98

44

100

37

83

34

86

3

3

8.9022 1.3143
Ratio 5.35448 3.2432 2.2523 1.6356 1.2106 1.0000 0.8651 0.7167 0.60148 - 4.7983

Nomogram

Planetary gearSet 1 - Planetary gearSet 2 - Planetary gearSet 3 - Planetary gearSet 4

▶️ Interactive Nomogram

This nomogram is a real geometric calculator exactly representing the rotational speeds of the transmission's 3x4 = 12 internal shafts for each of its 9 ratios (+ reverse), grouped according to their 4 permanent coupling on 3 joint ordinates and 5 independent ordinates. These ordinates are positioned on the abscissa in strict accordance with the proportions of the sun gears' teeth numbers relative to those of their rings. Consequently, the output ratios on the 3rd ordinate (carrier of the third planetary gearset) follows closely those of the actual transmission. This advantageous geometric construction sets us free from Willis' famous and tedious formula, because all calculations are exclusively determined by lengths ratios, respectively teeth numbers on the abscissa for the 4 epicyclic ratios, and of rotational speeds on the 3rd ordinate for the 10 gear ratios.

Legend:
A : Brake (blocks s2 sun gear)
B : Brake (blocks r3 ring gear)
C : Brake (blocks c1 carrier gear)
D : Clutch (couples c3 carrier gear with r4 ring gear)
E : Clutch (couples c1 carrier gear with r2 ring gear)
F : Clutch (couples s1 sun gear with c1 carrier gear)

Applications

Mercedes C-Class

Mercedes E-Class

Mercedes S-Class

Non Mercedes-Benz models

2021-present Aston Martin DBX

See also

Notes

  1. plus 1 reverse gear
  2. 4 simple planetary gearsets, 3 brakes, 3 clutches
  3. plus 2 reverse gears
  4. 4 planetary gearsets (Ravigneaux planetary gearset considered as 2), 4 brakes, 3 clutches
  5. First version with a gear ratio span wider than 9:1 as widest among longitudinal automatic transmissions for passenger cars at that time
  6. Second version introduced without notice with the Mercedes-Benz E-Class (W213) to reduce the step between gear 4 and 5 below the one of the 7G-Tronic (1.3684:1)

References

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