Not exactly, the system can run without being at 100%, it even has a handicapped mode where it lets you drive the car without the benefits of the 4matic (hence, why buy it?), similar to a failure to the A.B.S system, where you still have regular braking power without the advantages of the A.B.S.

Anyway, my M.B. tech advisor has always told me horror stories about the 4matics. In any case, if your dad can upgrade to a E 320 T, it would be a much better proposition than the 300TE, it has more power and some worthwile minor upgrades in the interior.

__________________
A. Rosich
CL 500, 1998
S 500 L, 1998
E 320 T, 1995 [Sadly sold ]