Transfer case (VG), function - GF28.10-P-0002VGC
MODEL 166 with TRANSMISSION 722.9 up to model year 2016
Block diagram
Sectional view of transfer case (except CODE 430 (On & Offroad package))
Sectional view of transfer case (AMG version)
Transfer case (VG), general
Permanent all-wheel drive has advantages not only off-road but also on roads which provide good grip. Permanent all-wheel drive increases the number of driven wheels, thus improving tire-to-road adhesion. As a result, slip is reduced and the driving power is distributed to all of the wheels. The distributed driving power results in higher traction and higher lateral stability at the driven wheels. The standard equipment includes permanent all-wheel drive with three open differentials (transfer case, rear axle and front axle). The torque split of 50:50 %between the front axle and rear axle is specified as a fixed value in the transfer case. The ratio of the transfer case is 1:1. The driver can use the off-road program button (with engine 157/276/278/642 and engine 651 with CODE 498 (Japan version)), except CODE 430 (On & Offroad package), which is located on the lower control panel control unit, to activate the off-road function (changed shift characteristic) in the automatic transmission (NAG2). A changed accelerator pedal curve in the CDI control unit or the ME-SFI [ME] control unit and the off-road ABS function in the Electronic Stability Program control unit is also activated. The driver can switch the downhill speed regulation on or off using the Downhill Speed Regulation button. The Downhill Speed Regulation button is also on the lower control panel control unit.
MODEL 166 with TRANSMISSION 722.9 up to model year 2016 with CODE 430 (On & off-road package)
In vehicles with CODE 430 (On & Offroad package), the CODE 489 (AIRMATIC (air suspension with level adjustment and adaptive damping system ADS)) is automatically included.
Sectional view of transfer case (with CODE 430 (On & Offroad package))
With CODE 430 (On & Offroad package)
A permanent all-wheel drive with a lockable differential (transfer case) and two open differentials (front axle and rear axle) is used in the on & off-road package option. The torque split of 50:50 between the front and rear axle is specified as a fixed value in the transfer case for an open interaxle differential lock clutch pack. The "Low/High" function in the transfer case can be used to select two gear ratios. The "High" on-road ratio is 1:1, the "Low" off-road reduction ratio is 2.93:1. The transfer case is controlled by the transfer case control unit. The driver can switch between the "High" on-road ratio and the "Low" reduction ratio using the Low Range button which is in the lower control panel control unit. The differential lock in the transfer case can be actuated by the driver via the off-road package transmission mode control. The off-road package transmission mode controller provides 6 setting options and is located on the off-road operating panel control unit which is in the center console.
The following control units are involved in control of the transfer case:
- Transfer case control unit
- Off-Road operating panel control unit
- Lower control panel control unit
- ME-SFI control unit (with gasoline engines)
- CDI control unit (with diesel engines)
- Electronic Stability Program control unit
- Fully integrated transmission control unit
- AIRMATIC control unit (with CODE 489 (AIRmatic (air suspension with level adjustment and adaptive damping system ADS)))
Further subfunctions are described in separate documents:
- Transfer case control, function (with CODE 430 (On & Offroad package))
- Downhill Speed Regulation, function
- Offroad transmission mode, function (with engine 157, 276, 278, 642 and transmission 722.9 except CODE 430 (On & Offroad package)), model 166 with engine 651 and transmission 722.9, 724.2 with CODE 498 (Japan version), except CODE 430 (On & Offroad package)
- "Low/High" shift, function (with CODE 430 (On & Offroad package))
- Interaxle differential lock function (with CODE 430 (On & Offroad package))
- Transfer case oil supply, function
| Transfer case (VG), power flow | MODEL 166 with TRANSMISSION 722.9 up to model year 2016 with CODE 430 (On & off-road package) |
GF28.10-P-0002-05VGC | |
| MODEL 166 with TRANSMISSION 722.9 up to model year 2016 without CODE 430 (On & off-road package) |
GF28.10-P-0002-05VGD | ||
| Transfer case control, function | MODEL 166 with TRANSMISSION 722.9 up to model year 2016 with CODE 430 (On & off-road package) |
GF28.19-P-3000VGC | |
| Downhill Speed Regulation, function | GF28.19-P-3600VGC | ||
| Offroad transmission mode, function | MODEL 166 with ENGINE 157 with TRANSMISSION 722.9 up to model year 2016 without CODE 430 (On & off-road package) MODEL 166 with ENGINE 276 with TRANSMISSION 722.9 up to model year 2016 without CODE 430 (On & off-road package) MODEL 166 with ENGINE 278 with TRANSMISSION 722.9 up to model year 2016 without CODE 430 (On & off-road package) MODEL 166 with ENGINE 642 with TRANSMISSION 722.9 up to model year 2016 without CODE 430 (On & off-road package) MODEL 166 with ENGINE 651 with TRANSMISSION 722.9 up to model year 2016 with CODE 498 (Japanese version) |
GF28.19-P-3601VGC | |
| Transfer case oil supply, function | GF28.55-P-3000VGC | ||
| "Low/High" shift mechanism, function | MODEL 166 with TRANSMISSION 722.9 up to model year 2016 with CODE 430 (On & off-road package) |
GF28.60-P-1000VGC | |
| Interaxle differential lock, function | MODEL 166 with TRANSMISSION 722.9 up to model year 2016 with CODE 430 (On & off-road package) |
GF28.60-P-3100VGC | |
| Overview of system components, transfer case (VG) | GF28.10-P-9998VGC |