The "old 4MATIC system" made available in North America from 90 to 93 (from 88 in Europe) is a four mode system. It is not a really complex system but can be difficult/expensive to repair or diagnose. The shifting modes are described as 0, 1, 2 and 3. Mode 0 is 0%/100% F/R 2WD, mode 1 is 35%/65% F/R 4WD, mode 2 is 50%/50% F/R 4WD and mode 3 adds locking rear differential (ASD) to mode 2. The front differential cannot be locked. The newer 4MATIC system is similar mechanically but does not include a locking transfer case nor a locking rear differential. The torque is transferred using the braking system rather than using clutches. Sensing slippage is the same in both systems, but how toque is transferred is different. The new system can handle slip at any 3 wheels and still be able the move while the old system would be stuck if both rear and one front wheel slipped.
Last edited by iread; 02-04-2002 at 01:32 PM.