Mercedes-Benz 9G-Tronic transmission

9G-Tronic is Mercedes-Benz's trademark name for its 9-speed automatic transmission, starting off with the W9A 700 (Wandler-9-Gang-Automatik bis 700 N⋅m Eingangsdrehmoment; converter-9-gear-automatic with Template:Convert maximum input torque; type 725.0) as core model. The transmission was used in the E 350 BlueTEC in 2013 for the first time, and successively replaced both the 7-speed 7G-Tronic (PLUS) transmission and the 5-speed 5G-Tronic transmission. It includes versions for a maximum input torque of Template:Convert.

After the 5G- and 7G-Tronic, this is the 3rd generation of modern automatic transmissions. It is identified internally as NAG3 (New Automatic Gearbox 3rd generation).

The Jatco 9AT transmission is based on the same globally patented gearset concept.

Development and production

Development took place at the group's headquarters in Stuttgart-Untertuerkheim. Initially, the transmission was produced only at the Daimler plant not far away in Stuttgart-Hedelfingen. Since April 2016, the transmission has also been produced at Daimler's subsidiary Star Assembly in Sebeș, Romania.

Licensing to Jatco Ltd

ln 2019, the Jatco Ltd, based in Fuji, Shizuoka, Japan, started licensed production for use in Nissan and Infiniti vehicles. In this version, input torque is limited to Template:Convert, allowing each of the gearsets 1, 2, and 4 to use only three planetary gears. Slightly modified gear dimensions give it a span of just under 9.1:1.

Specifications

Technical Data

Type	725.0			JR913E
Model	W9A 400	W9A 700	W9A 1000	9AT
Input Capacity
Maximum engine power
Maximum engine torque	Template:Convert	Template:Convert	Template:Convert	Template:Convert
Maximum shaft speed	1st to 7th: 7,000/min
	8th: 5,900/min
	9th: 5,000/min
Structure
Torque converter lock-up	with torsional + pendulum · can operate in all 9 forward gears
Torque converter size				Template:Convert
Length	Overall: Template:Convert to Template:ConvertTemplate:Efn			Gearbox only: Template:Convert
Fluid capacity	Template:Convert
WeightTemplate:Efn		Template:Convert		Template:Convert
Template:Notelist

Torque converter

One main focus was on increasing shift comfort, which is achieved on the one hand by measures in the control system and on the other hand by designing the torque converter accordingly. The hydrodynamic torque converter was largely taken over from the previous 7G-Tronic transmission.

Control system

The 9G-Tronic is fully electronically controlled. The shift elements are controlled via a new type of hydraulic direct control with electromagnetically actuated valves, which enables fast and smooth gear changes. Compared to the previous transmission, which had a hydraulic pilot control, leakage losses have been reduced by 80%.

Oil supply

The transmission is equipped with two oil pumps to ensure an energy-efficient supply of long-life synthetic fuel-economy low-friction oil: a mechanical rotary vane pump with chain drive, which is significantly smaller than its predecessor and located next to the main shaft, and a pump driven by a brushless electric DC motor. The mechanically driven pump is responsible for the basic supply of the transmission, with the flow rate depending on the speed of the drive motor. The additional pump is switched on by the electronic transmission control unit as required. This design enables the lubricating and cooling oil volume flow to be regulated as required and makes the 9G-Tronic start/stop-capable. When the drive motor is at a standstill, the transmission remains ready to start solely due to the supply from the electric auxiliary pump.

Filter elements for the two pumps are integrated in the plastic oil pan.

AMG SpeedShift 9G

AMG SpeedShift TCT 9G

The TCT 9G (Torque Converter Technology) transmission is essentially the 9G-Tronic.

AMG SpeedShift MCT 9G

Mercedes-AMG developed the MCT 9G (Multi Clutch Technology) transmission. It was first introduced in the Mercedes-AMG E 63 4Matic+.

The MCT transmission is essentially the 9G-Tronic with a start-off wet clutch (NAK for German Nass-Anfahrkupplung) replacing the torque converter. This saves weight and optimises the response to the accelerator pedal input. It is a computer-controlled double-clutching. The MCT acronym refers to this multiple-plate clutch. Its torque is rated at Template:Convert and it offers 4 drive modes: “C” (Comfort), “S” (Sport), “S+” (Sport plus) and “M” (Manual) and boasts 0.1 second shifts in “M” and “S+” modes. MCT-equipped cars are also fitted with the new AMG Drive Unit as the central control unit for all driving dynamics functions and an innovative Race Start Function.

The driver can change gears either using the steering-wheel shift paddles or conventionally the selector lever. The new Race Start Function is a launch control system that enables maximum acceleration while ensuring optimum traction of the driven wheels.

Progress Gearset Concept

Main Objectives

The main objectives in replacing the previous 7G-Tronic model were to improve fuel consumption by adding gears and increasing the gear span, while at the same time reducing manufacturing costs.

The wide gear spanTemplate:Efn allows the engine speed level to be lowered (downspeeding), which is a decisive factor in improving energy efficiency and thus reducing fuel consumption by 6.5 %. In addition, the lower engine speed level improves the noise-vibration-harshness comfort and the exterior noise is reduced by up to 4 dB(A). A speed of 120 km/h is reached in the Mercedes-Benz E 350 BlueTEC in 9th gear at an engine speed of approx. 1350 rpm. Unsurpassed ratio span among longitudinal automatic transmissions for passenger cars.Template:Efn

Extent

As the design of the predecessor was significantly more complex than that of the direct competitor 6HP and even the new 8HP model from ZF with one more gear, the specification sheet also stipulate that at least one shift element must be omitted. This was achieved thanks to high-speed computer-aided design and has resulted in a globally patented gearset concept that requires the same installation space as the previous model and is also Template:Convert lighter. In the process, 85 billion gearset concepts were examined. Additionally, the unit brings the ability to shift in a non-sequential manner – going from gear 9 to gear 4 in extreme situations simply by changing one shift element (actuating brake C and releasing brake A).

After the 5G- and 7G-Tronic, this transmission is the 3rd generation in which in-line epicyclic gearing have been combined with parallel epicyclic gearing. The resulting progress is reflected in an even better ratio between the number of gears and the number of components used compared to all layouts previously used by Mercedes-Benz.

Innovation Strength

With Asessment	Output: Gear Ratios	Innovation ElasticityTemplate:Efn Δ Output : Δ Input	Input: Main Components
			Total	Gearsets	Brakes	Clutches
W9A Ref. Object	$n_{O1}$ $n_{O2}$	TopicTemplate:Efn	$n_I=n_G+$ $n_B+n_C$	$n_{G1}$ $n_{G2}$	$n_{B1}$ $n_{B2}$	$n_{C1}$ $n_{C2}$
Δ Number	$n_{O1}-n_{O2}$		$n_{I1}-n_{I2}$	$n_{G1}-n_{G2}$	$n_{B1}-n_{B2}$	$n_{C1}-n_{C2}$
Relative Δ	Δ Output $\frac{n_{O1}-n_{O2}}{n_{O2}}$	$\frac{n_{O1}-n_{O2}}{n_{O2}}:\frac{n_{I1}-n_{I2}}{n_{I2}}$ $=\frac{n_{O1}-n_{O2}}{n_{O2}}$·$\frac{n_{I2}}{n_{I1}-n_{I2}}$	Δ Input $\frac{n_{I1}-n_{I2}}{n_{I2}}$	$\frac{n_{G1}-n_{G2}}{n_{G2}}$	$\frac{n_{B1}-n_{B2}}{n_{B2}}$	$\frac{n_{C1}-n_{C2}}{n_{C2}}$
W9A W7ATemplate:Efn	9Template:Efn 7Template:Efn	ProgressTemplate:Efn	10 11	4 4Template:Efn	3 4	3 3
Δ Number	2		-1	0	-1	0
Relative Δ	Template:Round $\frac{2}{7}$	Template:RoundTemplate:Efn $\frac{2}{7}:\frac{-1}{11}=\frac{2}{7}$·$\frac{-11}{1}=\frac{-22}{7}$	Template:Round $\frac{-1}{11}$	Template:Round $\frac{0}{4}$	Template:Round $\frac{-1}{4}$	Template:Round $\frac{0}{3}$
W9A 8HPTemplate:Efn	9Template:Efn 8Template:Efn	Current Market PositionTemplate:Efn	10 9	4 4	3 2	3 3
Δ Number	1		1	0	1	0
Relative Δ	Template:Round $\frac{1}{8}$	Template:Font color	Template:Round $\frac{1}{9}$	Template:Round $\frac{0}{4}$	Template:Round $\frac{1}{2}$	Template:Round $\frac{0}{3}$
W9A 3-SpeedTemplate:Efn	9Template:Efn 3Template:Efn	Historical Market PositionTemplate:Efn	10 7	4 2	3 3	3 2
Δ Number	6		3	2	0	1
Relative Δ	Template:Round $\frac{2}{1}$	Template:RoundTemplate:Efn $\frac{2}{1}:\frac{3}{7}=\frac{2}{1}$·$\frac{7}{3}=\frac{14}{3}$	Template:Round $\frac{3}{7}$	Template:Round $\frac{1}{1}$	Template:Round $\frac{0}{3}$	Template:Round $\frac{1}{2}$
Template:Notelist

Quality Gearset Concept

The ratios of the 9 gears are better distributed in all versions than in the direct competitors 8HP from ZF and much better than in the 10-speed transmissions from Ford/GM and Aisin/Toyota. The only noticeable weaknesses are the relatively small step between 5th and 6th gear and the too small one between 6th and 7th gear. These cannot be eliminated without affecting all other gears and thus impairing gear steps. On the other hand, this weaknesses are not overly significant.

All in all

• the extra effort, reflected in the acceptable elasticity compared to the ZF 8HP is more than justified and
• compared to the 10-speed gearboxes from Ford/GM and Aisin/Toyota, the absence of the 10th gear is more than compensated for by the significantly better distribution.

Gear Ratios

With Assessment			Weight	Planetary Gearset: TeethTemplate:Efn				Count	TotalTemplate:Efn CenterTemplate:Efn	Avg.Template:Efn
				Simpson		SimpleTemplate:Efn
Model Type	Version First Delivery		with Con- verter + Oil	S1Template:Efn R1Template:Efn	S2Template:Efn R2Template:Efn	S3Template:Efn R3Template:Efn	S4Template:Efn R4Template:Efn	Brakes Clutches	Ratio Span	Gear StepTemplate:Efn
Gear Ratio	R $i_R$	1 $i_1$	2 $i_2$	3 $i_3$	4 $i_4$	5 $i_5$	6 $i_6$	7 $i_7$	8 $i_8$	9 $i_9$
StepTemplate:Efn	$-\frac{i_R}{i_1}$Template:Efn	$\frac{i_1}{i_1}$	$\frac{i_1}{i_2}$Template:Efn	$\frac{i_2}{i_3}$	$\frac{i_3}{i_4}$	$\frac{i_4}{i_5}$	$\frac{i_5}{i_6}$	$\frac{i_6}{i_7}$	$\frac{i_7}{i_8}$	$\frac{i_8}{i_9}$
Δ StepTemplate:EfnTemplate:Efn			$\frac{i_1}{i_2}:\frac{i_2}{i_3}$	$\frac{i_2}{i_3}:\frac{i_3}{i_4}$	$\frac{i_3}{i_4}:\frac{i_4}{i_5}$	$\frac{i_4}{i_5}:\frac{i_5}{i_6}$	$\frac{i_5}{i_6}:\frac{i_6}{i_7}$	$\frac{i_6}{i_7}:\frac{i_7}{i_8}$	$\frac{i_7}{i_8}:\frac{i_8}{i_9}$
Shaft Speed	$\frac{i_1}{i_R}$	$\frac{i_1}{i_1}$	$\frac{i_1}{i_2}$	$\frac{i_1}{i_3}$	$\frac{i_1}{i_4}$	$\frac{i_1}{i_5}$	$\frac{i_1}{i_6}$	$\frac{i_1}{i_7}$	$\frac{i_1}{i_8}$	$\frac{i_1}{i_9}$
Δ Shaft SpeedTemplate:Efn	$0-\frac{i_1}{i_R}$	$\frac{i_1}{i_1}-0$	$\frac{i_1}{i_2}-\frac{i_1}{i_1}$	$\frac{i_1}{i_3}-\frac{i_1}{i_2}$	$\frac{i_1}{i_4}-\frac{i_1}{i_3}$	$\frac{i_1}{i_5}-\frac{i_1}{i_4}$	$\frac{i_1}{i_6}-\frac{i_1}{i_5}$	$\frac{i_1}{i_7}-\frac{i_1}{i_6}$	$\frac{i_1}{i_8}-\frac{i_1}{i_7}$	$\frac{i_1}{i_9}-\frac{i_1}{i_8}$
Torque RatioTemplate:Efn	$\frac{T_{2;R}}{T_{1;R}}$	$\frac{T_{2;1}}{T_{1;1}}$	$\frac{T_{2;2}}{T_{1;2}}$	$\frac{T_{2;3}}{T_{1;3}}$	$\frac{T_{2;4}}{T_{1;4}}$	$\frac{T_{2;5}}{T_{1;5}}$	$\frac{T_{2;6}}{T_{1;6}}$	$\frac{T_{2;7}}{T_{1;7}}$	$\frac{T_{2;8}}{T_{1;8}}$	$\frac{T_{2;9}}{T_{1;9}}$
EfficiencyTemplate:Efn	ηR	η1	η2	η3	η4	η5	η6	η7	η8	η9
W9A ALL 725.0	Template:Convert 2013Template:Efn		Template:Convert	46 98	44 100	36 84	34 86	3 3	Template:Round Template:Round	Template:RoundTemplate:Efn
Gear Ratio	Template:Font color	Template:Round $\frac{6,835}{1,242}$	Template:Round $\frac{10}{3}$	Template:Round $\frac{125}{54}$	Template:Font color	Template:Round $\frac{1,075}{888}$	Template:Font color	Template:Font colorTemplate:EfnTemplate:Efn $\frac{58,781}{67,944}$	Template:Round $\frac{43}{60}$	Template:Round $\frac{52,675}{87,576}$
Step	Template:Font color	1.0000	1.6510	1.4400	Template:Font color	1.3722	1.2106	Template:Font color	1.2072	1.1915
Δ StepTemplate:Efn			1.1465	1.0333	Template:Font colorTemplate:Efn	1.1335	1.0473	Template:Font colorTemplate:Efn	1.0131
Speed	Template:Font color	1.0000	1.6510	2.3774	3.3130	4.5459	Template:Font color	Template:Font color	7.6789	9.1495
Δ Speed	Template:Font color	1.0000	0.6510	0.7264	0.9356	1.2329	Template:Font colorTemplate:Efn	Template:Font colorTemplate:Efn	1.3178	1.4706
TorqueTemplate:Efn	–4.6393	5.2806	3.2633	2.2450	1.6274	1.1957	1.0000	0.8578	0.7104	0.5902
EfficiencyTemplate:Efn	0.9407	0.9595	0.9790	0.9698	0.9797	0.9877	1.0000	0.9915	0.9913	0.9813
W9A ALL 725.0	Template:Convert 2016Template:Efn		Template:Convert	46 98	44 100	37 83	34 86	3 3	Template:Round Template:Round	Template:RoundTemplate:Efn
Gear Ratio	Template:Font color	Template:Round $\frac{13,670}{2,553}$	Template:Round $\frac{120}{37}$	Template:Round $\frac{250}{111}$	Template:Font color	Template:Round $\frac{1,075}{888}$	Template:Font color	Template:Font color	Template:Round $\frac{43}{60}$	Template:Round $\frac{52,675}{87,576}$
Step	Template:Font color	1.0000	1.6510	1.4400	Template:Font color	1.3511	1.2106	Template:Font color	1.2072	1.1915
Δ StepTemplate:Efn			1.1465	1.0457	Template:Font colorTemplate:Efn	1.1160	1.0473	Template:Font colorTemplate:Efn	1.0131
Speed	Template:Font color	1.0000	1.6510	2.3774	3.2737	4.4231	Template:Font color	Template:Font color	7.4714	8.9022
Δ Speed	Template:Font color	1.0000	0.6510	0.7264	0.8964	1.1493	Template:Font colorTemplate:Efn	Template:Font colorTemplate:Efn	1.2822	1.4308
TorqueTemplate:Efn	–4.5151	5.1392	3.1759	2.1849	1.6031	1.1957	1.0000	0.8578	0.7104	0.5902
EfficiencyTemplate:Efn	0.9410	0.9598	0.9793	0.9701	0.9802	0.9877	1.0000	0.9915	0.9913	0.9813
Jatco 9AT JR913E	Template:Convert 2019Template:Efn		Template:Convert	45 96	41 91	38 86	37 92	3 3	Template:Round Template:Round	Template:RoundTemplate:Efn
Gear Ratio	Template:Font color	Template:Round $\frac{51,026}{9,405}$	Template:Round $\frac{62}{19}$	Template:Round $\frac{2,821}{1,254}$	Template:Font color	Template:Round $\frac{8,372}{6,855}$	Template:Font color	Template:Font color	Template:Round $\frac{92}{129}$	Template:Round $\frac{66,976}{112,227}$
Step	Template:Font color	1.0000	1.6626	1.4505	Template:Font color	1.3503	1.2213	Template:Font color	1.2085	1.1950
Δ StepTemplate:Efn			1.1462	1.0634	Template:Font colorTemplate:Efn	1.1056	1.0526	Template:Font colorTemplate:Efn	1.0113
Speed	Template:Font color	1.0000	1.6626	2.4117	3.2899	4.4423	Template:Font color	Template:Font color	7.6074	9.0910
Δ Speed	Template:Font color	1.0000	0.6626	0.7491	0.8782	1.1525	Template:Font colorTemplate:Efn	Template:Font colorTemplate:Efn	1.3124	1.4836
TorqueTemplate:Efn	–4.5149	5.2061	3.1953	2.1818	1.6161	1.2055	1.0000	0.8544	0.7069	0.5855
EfficiencyTemplate:Efn	0.9408	0.9596	0.9792	0.9699	0.9800	0.9871	1.0000	0.9914	0.9912	0.9810
Ratio R & Even	$i_R=-\frac{R_1{R}_2(S_3+R_3)}{S_1(S_2+R_2)S_3}$		$i_2=\frac{S_3+R_3}{S_3}$		$\frac{S_3(S_4+R_4)+R_3{S}_4}{S_3(S_4+R_4)}$Template:Efn		$i_6=\frac{1}{1}$	$i_8=\frac{R_4}{S_4+R_4}$
Ratio Odd	$\frac{(S_1(S_2+R_2)+R_1{S}_2)(S_3+R_3)}{S_1(S_2+R_2)S_3}$		$i_3=\frac{R_2(S_3+R_3)}{(S_2+R_2)S_3}$		$i_5=\frac{R_2{R}_4}{R_2{R}_4-S_2{S}_4}$		$\frac{R_4(S_1(S_2+R_2)+R_1{S}_2)}{S_1{R}_4(S_2+R_2)+R_1{S}_2(S_4+R_4)}$		$\frac{R_1{R}_2{R}_4}{S_1{S}_4(S_2+R_2)+R_1{R}_2(S_4+R_4)}$
Algebra And Actuated Shift ElementsTemplate:Efn
Brake ATemplate:Efn	❶								❶	❶
Brake BTemplate:Efn	❶	❶		❶	(❶)Template:Efn	❶		❶		❶
Brake CTemplate:Efn	❶	❶	❶	❶	❶Template:Efn
Clutch DTemplate:Efn			❶	❶		❶	❶
Clutch ETemplate:Efn		❶	❶				❶	❶	❶
Clutch FTemplate:Efn					❶Template:Efn	❶	❶	❶	❶	❶
Template:Notelist

Maintenance

Compared to the predecessor gearboxes NAG1 (5G-Tronic) and NAG2 (7G-Tronic), the NAG3 gearbox is much more highly integrated, meaning that repairs are only possible by replacing entire assemblies when servicing is required. This applies, for example, to the oil filters permanently integrated in the plastic oil pan. Another example is the fully integrated mechatronic module with sensors, control unit and electrohydraulic shift plate. This module must be replaced as a unit, even if, for example, only one sensor is defective.

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 Robert 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.

This nomogram reflects the version from 2013.

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 models

Mercedes C-Class

• 2018–2021 Mercedes-Benz W205 (all models)
• 2022–present Mercedes-Benz W206

Mercedes E-Class

• 2014–2016 Mercedes-Benz W212 (E 350 BlueTec only) available as an option to others.
• 2016–2023 Mercedes-Benz W213
• 2023–present Mercedes-Benz W214

Mercedes S-Class

• 2015–2021 Mercedes-Benz W222 (all except V12 models)
• 2021–present Mercedes-Benz W223

Mercedes V-Class

• 2020–present V-Class (W447) (longitudinal engines)

Mercedes GLC-Class

• 2015–2022 GLC (X253)
• 2022–present GLC (X254)

Mercedes-Benz GLE-Class

• 2016–2019 GLE (W166) (except 63 AMG & 350 models)
• 2020–present GLE (W167) (except 63 models)

Mercedes-Benz GLS-Class

• 2017–2019 GLS (X166) (all except AMG)
• 2020–present GLS (X167)

Mercedes-Benz SLK-Class

• 2015–2020 SLC (R172) (except 55 AMG)

Mercedes-AMG models

Mercedes-AMG SL

• 2022–present AMG SL (R232)

Jatco Ltd model JR913E

Nissan

• 2020–2024 Nissan Titan
• 2020–present Nissan Frontier
• 2023–present Nissan Z (RZ34)

Aston Martin

• 2021–present Aston Martin DBX

See also

• List of Daimler AG transmissions
• List of Jatco transmissions

External links

• Nine-Speed Automatic Transmission 9G-Tronic by Mercedes-Benz
• Nomographs and Feasibility Graphs for Enumeration of Ravigneaux-Type Automatic Transmissions