G-Tronic is a series of automatic transmissions with manual mode, installed on Mercedes-Benz and SsangYong vehicles. The first G-Tronic was a 4-speed automatic transmission launched in 1981. Today, the manufacturer produces a 9-speed G-Tronic transmission. All these gearboxes are proprietary developments of Daimler AG. They are characterized by their reliability, high performance, and can transmit high torque.
G-TRONIC OPERATING PRINCIPLE
The G-Tronic is based on a classic automatic transmission with a hydraulic torque converter and electronic control. From the 90s onwards, it features a torque converter lock-up. Initially, this allowed a driver to select a higher gear (one or more higher gears could be locked). Later, it helped implement a full manual mode on all subsequent generations of this automatic transmission.
Typically, these transmissions have several automatic operating modes, for example, Sport, Comfort, Eco. The driver can select the desired mode using a button, a special switch, or a selector on the center console. To switch to manual mode, the gear selector must be placed in the “D” position and then pushed to the left, towards the “-” sign. This locks the currently engaged gear. Then, you can upshift or downshift by pushing the selector towards “+” or “-“, respectively. Manual gear shifting can also be performed using paddle shifters (if the vehicle is equipped with them).
POPULAR G-TRONIC TRANSMISSIONS
| Version | Gearbox Code | Number of Gears | Maximum Engine Capacity, L | Maximum Engine Torque, N⋅m | Start of Production | Car Layout | Mercedes-Benz Models |
| 4G-Tronic | 722.3 (W4A040) | 4 | 6.0 | 570 | 1981 | RWD | S-Class W126; E-Class W123; S-Class W140; SL R107; E-Class W124; SL R129 |
| 4G-Tronic | 722.4 (W4A020) | 4 | 3.0 | 250 | 1981 | RWD | S-Class W126; E-Class W123; C-Class W202; E-Class W124 |
| 5G-Tronic | 722.6 (W5A330, W5J400, W5A580) | 5 | 3.5; 4.3; 6.0 | 350; 420; 580 | 1996 | RWD, AWD | C-Class W202; S-Class W221; C-Class W204; E-Class W211; C-Class W203; E-Class W212; M-Class W163; S-Class W140; S-Class W220 |
| 5G-Tronic | 722.7 (W5A180) | 5 | 1.9 | 205 | 1998 | FWD | Vaneo W414; A-Class W168 |
| 7G-Tronic | 722.9 (W7X550, W7A700, W7B700) | 7 | 3.5; 5.5; 6.3 | 550; 700; 850 | 2003 | RWD, AWD | C-Class W204; S-Class W221; E-Class W211; S-Class W220; M-Class W164; C-Class W205; E-Class W212; M-Class W166 |
| 9G-Tronic | 725.0 (NAG3) | 9 | 6.7 | 1000 | 2013 | RWD, AWD | C-Class W205; GLE W166; S-Class W222; E-Class W213; GLS X166; CLS W218 |
COMMON MALFUNCTIONS OF G-TRONIC TRANSMISSIONS
| Malfunctions | Transmissions |
| A clogged transmission oil cooler causes the transmission to overheat. | 722.4 (W4A020); 722.3 (W4A040) |
| A spring in the reverse clutch pack fails. | 722.3 (W4A040); 722.4 (W4A020) |
| The vacuum modulator valve often fails. | 722.4 (W4A020); 722.3 (W4A040) |
| A bushing between the transmission shafts has insufficient strength and often fails. | 722.6 (W5A330, W5J400, W5A580) |
| The solenoids in the valve body become clogged with wear debris from the clutch packs. | 722.6 (W5A330, W5J400, W5A580) |
| The torque converter lock-up solenoid stops working prematurely. | 722.6 (W5A330, W5J400, W5A580) |
| A printed circuit board in the valve body often fails. | 722.7 (W5A180); 722.9 (W7A700, W7X550, W7B700) |
| One of the clutch drums is damaged. | 722.7 (W5A180) |
| Vibrations caused by aggressive driving behavior lead to severe damage to the transmission housing. | 722.9 (W7B700, W7X550, W7A700) |
| Transmission malfunctions caused by contamination and failure to replace the transmission fluid on time. | 725.0 (NAG3) |