on which side is the front differential located, driver's side or passenger side?

can the AWD / 4 WD system be actived on the fly or do we need to come to a full stop?

Cheers,

 

124 Chassis, the front differential is on the driver's side of the engine. To use the correct name, the 4MATIC system is automatic and controlled by computer as it detects slip. The driver does not do anything at speed or when stopped.

 

Is there a way to disable the 4MATIC? I had a Subaru outback that had 4WD and you could simply disable by inserting a fuse into the "FWD" block under the hood. This provided great gas mileage. (about +6mpg)
Then I could put it back to 4WD in winter.

 

To disable the 4-Matic operation, flip up the "test lever" between the wind screen fluid tank and expansion chamber. That will completlely bypass the transfer case, and it will be 100% 2WD.

Another possible way is to remove the light bulb. Check this thread out though flipping a switch sounds easier to me.

http://www.benzworld.org/forums/w124...91-300-te.html

Unless you have issues with your transmission I don't think you will be saving much gas by disabling it. All the power goes to the rear wheels unless there is slippage issue detected. At that point the 4matic system will kick in. This is the explanation from Wikiopedia on how it works

The first generation 4Matic system was originally a complex electronically controlled system with automatically engaging four-wheel drive (4WD), the system employs locking central and rear differentials to provide additional traction in slippery conditions. The centre differential, also known as the transfer case, contains two clutches. Each hydraulically enabled clutch is controlled separately to allow for three modes of operation: 2WD (mode 0) where 100% of available torque is available to the rear axle while the front axle is disconnected, and two 4WD modes which allow for 35/65 front/rear axle torque split (mode 1) or 50/50 front/rear axle torque split (mode 2). The rear differential lock, previously known as ASD on Mercedes-Benz models, can also be locked (mode 3) if rear wheel slip is still present when the transfer case 50/50 4WD mode 2 is engaged. Due to safety and stability concerns there is no front differential lock. The 4Matic system uses inputs from the three channel ABS system and a steering wheel angle sensor to decide when to intervene. 4WD is disengaged automatically if the ABS service brakes are applied. Engine throttle control is not inherent in the W124 system. Two W124 variants of the 4Matic system were produced: the first system (1986–1991) used a mechanical pressure test lever to disable the system hydraulically while the second system variant (1992/1993) used an electrical test switch to break power to the system. The latter system variant when in test mode allows for continued operation of the rear shock self-levelling system (SLS) when installed. Plagued with reliability problems at first, the multi-plate clutch central differentials were prone to failure; it was withdrawn in 1993.[2]