| 7G-Tronic | |
| Production: | 2003–2020 |
| Manufacturer: | Daimler AG |
| Class: | 7-speed longitudinal automatic transmission |
| Predecessor: | Mercedes-Benz 5G-Tronic transmission |
| Successor: | Mercedes-Benz 9G-Tronic transmission |
7G-Tronic is Mercedes-Benz's trademark name for its seven-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 seven-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 five different eight-cylinder models: the E500, S 430, S 500, CL 500, and SL 500. It also soon became available on many six-cylinder models. Turbocharged V12 engines, four 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. It has two reverse gear ratios.
The transmission can skip gears when downshifting. It also has a torque converter lock-up on all seven 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. The 7G-Tronic transmission is built at the Mercedes-Benz Stuttgart-Untertuerkheim plant in Germany, the site of Daimler-Benz's original production facility.
The transmission is currently available on the SsangYong's vehicles like Rexton, and Korando Turismo (in South Korea)/Turismo (in UK). In July 2009, Mercedes-Benz announced they are working on a new nine-speed automatic.[2]
Progress is reflected in 7 forward gears using 11 main components,[3] [4] compared to 5 forward gears 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. It is fully electronic controlled. Torque converter lock-up can operate in all 7 forward gears.
| With Assessment | Planetary Gear Set: Teeth | Count | Total | Avg. | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Ravigneaux | Simple | |||||||||
| Model Type | Version First Delivery | S1 R1 | S2 R2 | S3 R3 | S4 R4 | Brakes Clutches | Ratio Span | Gear Step | ||
| Gear Ratio | {iR3 | R 2 {iR2 | R 1 {iR1 | 1 {i1} | 2 {i2} | 3 {i3} | 4 {i4} | 5 {i5} | 6 {i6} | 7 {i7} |
| Step | \tfrac{iR1 | -\tfrac{iR1 | \tfrac{i1}{i1} | \tfrac{i1}{i2} | \tfrac{i2}{i3} | \tfrac{i3}{i4} | \tfrac{i4}{i5} | \tfrac{i5}{i6} | \tfrac{i6}{i7} | |
| Step 2 | \tfrac{i1}{i2}:\tfrac{i2}{i3} | \tfrac{i2}{i3}:\tfrac{i3}{i4} | \tfrac{i3}{i4}:\tfrac{i4}{i5} | \tfrac{i4}{i5}:\tfrac{i5}{i6} | \tfrac{i5}{i6}:\tfrac{i6}{i7} | |||||
| Shaft Speed | \tfrac{i1}{iR2 | \tfrac{i1}{iR1 | \tfrac{i1}{i1} | \tfrac{i1}{i2} | \tfrac{i1}{i3} | \tfrac{i1}{i4} | \tfrac{i1}{i5} | \tfrac{i1}{i6} | \tfrac{i1}{i7} | |
| Δ Shaft Speed | \tfrac{i1}{iR1 | 0-\tfrac{i1}{iR1 | \tfrac{i1}{i1}-0 | \tfrac{i1}{i2}-\tfrac{i1}{i1} | \tfrac{i1}{i3}-\tfrac{i1}{i2} | \tfrac{i1}{i4}-\tfrac{i1}{i3} | \tfrac{i1}{i5}-\tfrac{i1}{i4} | \tfrac{i1}{i6}-\tfrac{i1}{i5} | \tfrac{i1}{i7}-\tfrac{i1}{i6} | |
| W7A ALL 722.9 | 700Nm 2003 | 42 86 | 86 110 | 28 76 | 46 114 | 4 3 | ||||
| Gear Ratio | \tfrac{598}{399} | \tfrac{38,272}{17,157} | \tfrac{203,840}{46,569} | \tfrac{133,120}{46,569} | \tfrac{2,080}{1,083} | |||||
| Step | 1.5313 | 1.0000 | 1.4884 | 1.2189 | 1.1276 | |||||
| Step 2 | 1.0288 | 1.0605 | 1.1226 | 1.0810 | ||||||
| Speed | –1.9622 | –1.2815 | 1.0000 | 1.5313 | 2.2791 | 3.1987 | 4.3772 | |||
| Δ Speed | 0.6808 | 1.2815 | 1.0000 | 0.5313 | 0.7478 | 0.9196 | 1.1785 | |||
| Ratio R & even | iR3=-\tfrac{S4(S3+R3)}{S3R4} | -\tfrac{S4(S1+R1)(S3+R3)}{R1S3R4} | \tfrac{(S1+R1)(S3+R3)(S4+R4)}{R1R3R4} | i4=\tfrac{S3+R3}{R3} | \tfrac{S4(S1+R1)(S3+R3)}{S4(S1+R1)(S3+R3)+S1S3R4} | |||||
| Ratio R1 & odd | iR1=-\tfrac{S4(S2+R2)(S3+R3)}{S2S3R4} | \tfrac{(S2+R2)(S3+R3)(S4+R4)}{S2R3R4} | \tfrac{(S3+R3)(S4+R4)}{R3R4} | i5=\tfrac{1}{1} | \tfrac{S4(S2+R2)(S3+R3)}{S4(S2+R2)(S3+R3)+R2S3R4} | |||||
| Algebra And Actuated Shift Elements | ||||||||||
| Brake 1 | ❶ | ❶ | ❶ | |||||||
| Brake 2 | ❶ | ❶ | ❶ | ❶ | ||||||
| Brake 3 | ❶ | ❶ | ❶ | |||||||
| Brake BR | ❶ | ❶ | ||||||||
| Clutch 1 | ❶ | ❶ | ❶ | |||||||
| Clutch 2 | ❶ | ❶ | ❶ | ❶ | ||||||
| Clutch 3 | ❶ | ❶ | ❶ | ❶ | ❶ | ❶ | ❶ | ❶ | ||
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.[5]
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.[6]
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.[5]
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.[7]
In 2007, 7G-Tronic transmission with AMG SPEEDSHIFT was also called '7G-Tronic Sport'.[8]
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.[9]
The MCT is fitted with four 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.