Mercedes-Benz 7G-Tronic transmission

7G-Tronic
Overview
Manufacturer	Daimler AG
Production	2003–2020
Body and chassis
Class	7-speed longitudinal automatic transmission
Related	ZF 6HP · ZF 8HP
Chronology
Predecessor	5G-Tronic
Successor	9G-Tronic

7G-Tronic is Mercedes-Benz's trademark name for its 7-speed automatic transmission, starting off with the W7A 700 and W7A 400 (Wandler-7-Gang-Automatik bis 700 oder 400 Nm Eingangsdrehmoment; converter-7-gear-automatic with 516 or 295 ft·lb maximum input torque; type 722.9) as core models.

This fifth-generation transmission was the first 7-speed automatic transmission ever used on a production passenger vehicle.^[1] In all applications this transmission is identified as the New Automatic Gearbox Generation Two, or NAG2. It initially debuted in Autumn 2003 on 5 different V8-cylinder models: the E500, S 430, S 500, CL 500, and SL 500. It also soon became available on many 6-cylinder models. Turbocharged V12 engines, 4-cylinder applications and commercial vehicles continued to use the older Mercedes-Benz 5G-Tronic transmission for many years.

The company claims that the 7G-Tronic is more fuel efficient and has shorter acceleration times and quicker intermediate sprints than the outgoing 5-speed automatic transmission.^[1] It has 2 reverse gears.

The transmission can skip gears when downshifting. It also has a torque converter lock-up on all 7 gears, allowing better transmission of torque for improved acceleration. The transmission's casing is made of magnesium alloy, a first for the industry, to save weight.^{[citation needed]} The 7G-Tronic transmission is built at the Mercedes-Benz Stuttgart-Untertuerkheim plant in Germany, the site of Daimler-Benz's original production facility.

In July 2009, Mercedes-Benz announced they are working on a new nine-speed automatic.^[2]

In normal condition it sequentially shift gears, but if required it can skip some gears, that are: 7 to 5, 6 to 2, 5 to 3 and 3 to 1.^[3]

On vehicles with 6 or 8 cylinder engines with comfort mode engaged, as well as on off-road vehicles with low range selected, the transmission will always use 2nd gear as initial gear.^[4]

If the transmission control unit senses a critical fault during driving, it will activate an emergency operating mode: Upon hydraulic failures, it will stop shifting gears and permanently retain the currently selected gear; if the failure can be pinpointed to one of the internal hydraulic control valves, the transmission will continue shifting but stop using the affected gear(s). Upon electrical failure, the transmission shifts to 6th gear. If the critical fault persists after the vehicle is stopped and the engine restarted, only 2nd gear and reverse gear #2 are available.^[3]

The TCT transmission is essentially the 7G-Tronic automatic transmission including "Torque Converter Technology".

Sporty, performance-oriented version with the same gear ratios. First used in 2005 Mercedes-Benz SLK 55 AMG.^[5]

In 2007, 7G-Tronic transmission with AMG SPEEDSHIFT was also called '7G-Tronic Sport'.^[6]

Mercedes-AMG developed the 7-speed MCT "Multi Clutch Technology" planetary automatic transmission.

The MCT transmission is essentially the 7G-Tronic automatic transmission without a torque converter. Instead of a torque converter, it uses a compact wet startup clutch to launch the car from a stop and also supports computer-controlled double-clutching. The MCT (Multi-Clutch Technology) acronym refers to a planetary (automatic) transmission's multiple clutches and bands for each gear.^[7]

The MCT is fitted with 4 drive modes: "C" (Comfort), "S" (Sport), "S+" (Sport plus) and "M" (Manual) and boasts 100 millisecond shifts in "M" and "S+" modes. MCT-equipped cars are also fitted with the new AMG DRIVE UNIT with an innovative Race Start function. The AMG DRIVE UNIT is the central control unit for the AMG SPEEDSHIFT MCT 7-speed sports transmission and all driving dynamics functions. The driver can change gears either using the selector lever or by nudging the steering-wheel shift paddles. The new Race start Function is a launch control system that enables the driver to call on maximum acceleration while ensuring optimum traction of the driven wheels.

It is available on the 2009 SL 63 AMG and E 63 AMG, and will be used for the 2011 S 63 AMG and CL 63 AMG, and the 2012 CLS 63 AMG and C 63 AMG.

Compulsory on the 2014 AMG CLS 63 and E 63 models, as well as their "S--Model" variants. Improved with the release of the 2015 model year, by decreasing the lag time between shifts.

Progress is reflected in 7 forward gears^[a] using 11 main components,^[8][3][9] compared to 5 forward gears^[b] with 9 main components in the previous 5G-Tronic transmission. This turns out the design as advanced compared to its predecessor but less economical compared to its competitors. It uses no bands nor sprag clutches.^[3] It is fully electronic controlled. Torque converter lock-up can operate in all 7 forward gears.^[3]

Gear Ratios

With Assessment				Planetary Gear Set: Teeth[a]				Count	Total[b] Center[c]	Avg.[d]
				Ravigneaux		Simple
Model Type	Version First Delivery			S1[e] R1[f]	S2[g] R2[h]	S3[i] R3[j]	S4[k] R4[l]	Brakes Clutches	Ratio Span	Gear Step[m]
Gear Ratio	R 3[n] ${\displaystyle {i_{R3}}}$	R 2 ${\displaystyle {i_{R2}}}$	R 1 ${\displaystyle {i_{R1}}}$	1 ${\displaystyle {i_{1}}}$	2 ${\displaystyle {i_{2}}}$	3 ${\displaystyle {i_{3}}}$	4 ${\displaystyle {i_{4}}}$	5 ${\displaystyle {i_{5}}}$	6 ${\displaystyle {i_{6}}}$	7 ${\displaystyle {i_{7}}}$
Step[m]	${\displaystyle {\tfrac {i_{R2}}{i_{R3}}}}$	${\displaystyle {\tfrac {i_{R1}}{i_{R2}}}}$	${\displaystyle -{\tfrac {i_{R}}{i_{1}}}}$[o]	${\displaystyle {\tfrac {i_{1}}{i_{1}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{2}}}}$[p]	${\displaystyle {\tfrac {i_{2}}{i_{3}}}}$	${\displaystyle {\tfrac {i_{3}}{i_{4}}}}$	${\displaystyle {\tfrac {i_{4}}{i_{5}}}}$	${\displaystyle {\tfrac {i_{5}}{i_{6}}}}$	${\displaystyle {\tfrac {i_{6}}{i_{7}}}}$
Δ Step[q][r]		${\displaystyle {\tfrac {i_{R1}}{i_{R2}}}:{\tfrac {i_{R2}}{i_{R3}}}}$			${\displaystyle {\tfrac {i_{1}}{i_{2}}}:{\tfrac {i_{2}}{i_{3}}}}$	${\displaystyle {\tfrac {i_{2}}{i_{3}}}:{\tfrac {i_{3}}{i_{4}}}}$	${\displaystyle {\tfrac {i_{3}}{i_{4}}}:{\tfrac {i_{4}}{i_{5}}}}$	${\displaystyle {\tfrac {i_{4}}{i_{5}}}:{\tfrac {i_{5}}{i_{6}}}}$	${\displaystyle {\tfrac {i_{5}}{i_{6}}}:{\tfrac {i_{6}}{i_{7}}}}$
Shaft Speed	${\displaystyle {\tfrac {i_{1}}{i_{R3}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{R2}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{R1}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{1}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{2}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{3}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{4}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{5}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{6}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{7}}}}$
Δ Shaft Speed[s]	${\displaystyle {\tfrac {i_{1}}{i_{R2}}}-{\tfrac {i_{1}}{i_{R3}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{R1}}}-{\tfrac {i_{1}}{i_{R2}}}}$	${\displaystyle 0-{\tfrac {i_{1}}{i_{R1}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{1}}}-0}$	${\displaystyle {\tfrac {i_{1}}{i_{2}}}-{\tfrac {i_{1}}{i_{1}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{3}}}-{\tfrac {i_{1}}{i_{2}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{4}}}-{\tfrac {i_{1}}{i_{3}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{5}}}-{\tfrac {i_{1}}{i_{4}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{6}}}-{\tfrac {i_{1}}{i_{5}}}}$	${\displaystyle {\tfrac {i_{1}}{i_{7}}}-{\tfrac {i_{1}}{i_{6}}}}$
W7A ALL 722.9	700 N⋅m (516 lb⋅ft) 2003[8][9]			42 86	86 110	28 76	46 114	4 3	6.0162 1.7846	1.3486[m]
Gear Ratio	−1.4987[n] ${\displaystyle {\tfrac {598}{399}}}$	−2.2307 ${\displaystyle {\tfrac {38,272}{17,157}}}$	−3.4157[o] ${\displaystyle -{\tfrac {8,372}{2,451}}}$	4.3772 ${\displaystyle {\tfrac {203,840}{46,569}}}$	2.8586[r] ${\displaystyle {\tfrac {133,120}{46,569}}}$	1.9206 ${\displaystyle {\tfrac {2,080}{1,083}}}$	1.3684[r] ${\displaystyle {\tfrac {26}{19}}}$	1.0000[m] ${\displaystyle {\tfrac {1}{1}}}$	0.8204[s] ${\displaystyle {\tfrac {38,272}{46,651}}}$	0.7276[s] ${\displaystyle {\tfrac {8,372}{11,507}}}$
Step	1.4884	1.5313	0.7804[o]	1.0000	1.5313	1.4884	1.4035	1.3684[m]	1.2189	1.1276
Δ Step[q]		1.0288			1.0288[r]	1.0605	1.0256[r]	1.1226	1.0810
Speed	–2.9205	–1.9622	-1.2815	1.0000	1.5313	2.2791	3.1987	4.3772	5.3355	6.0162
Δ Speed	0.9583	0.6808	1.2815	1.0000	0.5313	0.7478	0.9196	1.1785	0.9583[s]	0.6808[s]
Ratio R & Even	${\displaystyle i_{R3}=-{\tfrac {S_{4}(S_{3}+R_{3})}{S_{3}R_{4}}}}$		${\displaystyle -{\tfrac {S_{4}(S_{1}+R_{1})(S_{3}+R_{3})}{R_{1}S_{3}R_{4}}}}$		${\displaystyle {\tfrac {(S_{1}+R_{1})(S_{3}+R_{3})(S_{4}+R_{4})}{R_{1}R_{3}R_{4}}}}$		${\displaystyle i_{4}={\tfrac {S_{3}+R_{3}}{R_{3}}}}$		${\displaystyle {\tfrac {S_{4}(S_{1}+R_{1})(S_{3}+R_{3})}{S_{4}(S_{1}+R_{1})(S_{3}+R_{3})+S_{1}S_{3}R_{4}}}}$
Ratio R1 & Odd	${\displaystyle i_{R1}=-{\tfrac {S_{4}(S_{2}+R_{2})(S_{3}+R_{3})}{S_{2}S_{3}R_{4}}}}$			${\displaystyle {\tfrac {(S_{2}+R_{2})(S_{3}+R_{3})(S_{4}+R_{4})}{S_{2}R_{3}R_{4}}}}$		${\displaystyle {\tfrac {(S_{3}+R_{3})(S_{4}+R_{4})}{R_{3}R_{4}}}}$		${\displaystyle i_{5}={\tfrac {1}{1}}}$	${\displaystyle {\tfrac {S_{4}(S_{2}+R_{2})(S_{3}+R_{3})}{S_{4}(S_{2}+R_{2})(S_{3}+R_{3})+R_{2}S_{3}R_{4}}}}$
Algebra And Actuated Shift Elements[t]
Brake 1[u]		❶			❶				❶
Brake 2[v]				❶	❶	❶	❶
Brake 3[w]			❶	❶						❶
Brake BR[x]	❶[n]	❶	❶
Clutch 1[y]	❶[n]					❶	❶	❶
Clutch 2[z]							❶	❶	❶	❶
Clutch 3[aa]	❶[n]	❶	❶	❶	❶	❶		❶	❶	❶
^ Layout Input and output are on opposite sides Planetary gearset 2 (the outer Ravigneaux gearset) is on the input (turbine) side Input shafts are R1 and, if actuated, R3 Output shaft is C3 (planetary gear carrier of gearset 3) ^ Total Ratio Span (Total Ratio Spread · Total Gear Ratio) ${\displaystyle {\tfrac {i_{n}}{i_{1}}}}$ 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 ^ Ratio Span's Center ${\displaystyle (i_{n}i_{1})^{\tfrac {1}{2}}}$ 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 ${\displaystyle ({\tfrac {i_{n}}{i_{1}}})^{\tfrac {1}{n-1}}}$ With decreasing step width the gears connect better to each other shifting comfort increases ^ Sun 1: sun gear of gearset 1: inner Ravigneaux gearset ^ Ring 1: ring gear of gearset 1: inner Ravigneaux gearset ^ Sun 2: sun gear of gearset 2: outer Ravigneaux gearset ^ Ring 2: ring gear of gearset 2: outer Ravigneaux gearset ^ Sun 3: sun gear of gearset 3 ^ Ring 3: ring gear of gearset 3 ^ Sun 4: sun gear of gearset 4 ^ Ring 4: ring gear of gearset 4 ^ a b c d e Standard 50:50 — 50 % Is Above And 50 % Is Below The Average Gear Step — 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 3) is always larger and the upper half of the gear steps (between the large gears; rounded up, here the last 3) 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 In line with the logic for the 2nd reverse gear of the predecessor 5G-Tronic, the extended layout provides this 3rd reverse gear, but it was not used in the transmission that was finally launched on the market ^ a b c Standard R:1 — Reverse And 1st Gear Have The Same Ratio — 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 — Gear Step 1st To 2nd Gear As Small As Possible — 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 d e Standard STEP — From Large To Small Gears: Steady And Progressive Increase In Gear Steps — Gear steps should increase: Δ Step (first green highlighted line Δ Step) is always greater than 1 As progressive as possible: Δ Step is always greater than the previous step Not progressively increasing is acceptable (red) Not increasing is unsatisfactory (bold) ^ a b c d e Standard SPEED — From Small To Large Gears: Steady Increase In Shaft Speed Difference — 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) ^ Permanently coupled elements C1 and C2 (the common Ravigneaux carrier 1 + 2), and R4 R3 and C4 (carrier 4) ^ Blocks S1 (sun gear of the inner Ravigneaux geaset) ^ Blocks S3 ^ Blocks R2 (ring gear of the outer Ravigneaux gearset) ^ Blocks R3 and C4 (carrier 4) ^ Couples S1 (sun gear of inner Ravigneaux gearset) with R2 (ring gear of outer Ravigneaux gearset) ^ Couples R1 (ring of inner Ravigneaux gearset) with R3 and C4 (carrier 4) ^ Couples S3 with S4

• 2005-2007 Mercedes-Benz W203 (C 320 CDI, C 230, C 280, C 350; post-facelift)
• 2005-2007 Mercedes-Benz CL203 (C 230 SportCoupé, C 350 SportCoupé; post-facelift), (CLC 250, CLC 350)
• 2011–2018 Mercedes-Benz W204 (C 63 AMG, C 63 AMG Black Series)
• 2014 Mercedes-Benz W205 (C 180)

• 2009–2016 Mercedes-Benz W212 (E200AMG 7G-Tronic,E63AMG)
• 2009–2013 Mercedes-Benz W212 (E200AMG 7G-Tronic)
• 2005–2009 Mercedes-Benz W211 (E350 v6 7G-Tronic)

• 2013–2017 Mercedes-Benz W222 (all models except Maybach S 500 and Maybach S 500 4MATIC)
• 2017–2020 Mercedes-Benz W222 (V12 models only)

• 2004–2011 Mercedes-Benz R171
• 2011–2015 Mercedes-Benz R172

• 2003-2010 Mercedes-Benz C219
• 2010-2018 Mercedes-Benz C218

• 2002–2010 Mercedes-Benz C209

• 2014–2019 Infiniti Q50 (2.0t (M274 DE20 LA)^[10]).
• 2015–2016 Infiniti Q50 (2.2d (OM651 22 LA)^[11]).
• 2017–2018 Infiniti Q60 (2.0t (M274 DE20 LA)).

• 2017–2020 SsangYong Rexton G4 (2.2 e-XDi Euro 6 Turbo-Diesel)
• SsangYong Rodius Korando Turismo (in South Korea)
• SsangYong Rodius Turismo (in UK)

• List of Daimler AG transmissions

• 7g-Tronic ECU Repair
• GermanCarFans
• "7G-Tronic: Mercedes-Benz presents the world's first seven-speed automatic transmission for passenger cars" (PDF). DaimlerChrysler press release. Archived from the original (PDF) on 6 July 2011. Retrieved 14 October 2008.
• ATT24 GmbH