Mercedes-Benz 9G-Tronic transmission

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9G-Tronic
Overview
Manufacturer Daimler AG
Production 2013–
Body and chassis
Class 9-speed longitudinal automatic transmission
Chronology
Predecessor Mercedes-Benz 7G-Tronic transmission

9G-Tronic (codename 725.0) is Mercedes-Benz's trademark name for its nine-speed automatic transmission.[1] This transmission was introduced in 2013. It is the world's first nine-speed transmission. It was first used in the Mercedes-Benz S-Class (W222), and 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 GLE250d model. V12 engine models continue to use the older Mercedes-Benz 7G-Tronic transmission. Wide ratio spread of 9.30:1.

Gear ratios[edit]

Gear 1 2 3 4 5 6 7 8 9 R
9G TRONIC 5.502 3.3 2.315 1.661 1.210 1.000 0.865 0.717 0.602 -4.932

9G-Tronic Nomogram[edit]

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)

See also[edit]

References[edit]