Can I disengage the 4matic from w124?

[ant13dc]

Hi, the 4matic system on my 1990 w124 300td does not come on when i climb some back roads and the back wheels start to spin. Could I disconnect and use it rear wheel drive only? Would there be any issues? Would I get better performance?

 

[kth286]

My understanding is that it's not in use anyway as standard, and should
only become engaged when slip of a wheel/s is sensed.

There is an isolating lever in engine compartment (wing) which can be moved to position B to isolate the system due to a malfunction of electronics or hydraulics until such time it can be fixed.

Which position is that lever in - A or B ?

 

[def90cars]

If it is not working, then the centre diff is disengaged.
In Mode 0 the front is disengaged anyway.
Sounds to me like the centre diff is not engaging in Mode 1, 2 and 3

Or I may be talking nonsense

 

[bolide]

I believe there's an early and a late 4Matic system and only the early one has the lever under the bonnet

The system works by comparing wheel speeds via the ABS sensors and reading steering angle. It is disabled above a certain speed - 32 mph? I can't remember

The easiest way to test if it's working is a quick start on a flat, slippery surface. Have someone outside the car see which wheels spin

I think most 4Matics are 2WD by now

Nick Froome