Originally Posted by babymog

I believe that '91 was a transition year from the early to the later control portion, early one has a red lever next to the hydraulic reservoir just inside the fender to shut off the 4matic (hydraulicaly), the later has a rotary switch on the electronic module near the battery. I know of no reason that either is better than the other.

I had a '91 300TE 4matic. It did everything well, but had several problems during my ownership, including having the transfer-case re-sealed twice (by the dealer) by the time I sold it in '96 with IIRC 119,000miles on it. I referred to it as "the problematic". It was dealer maintained on most items, the minor things including detailing by me meticulously, still looked and smelled new when I sold her (see photo in my profile taken in '96 just before selling her) so maintenance wasn't an issue.

Its all-wheel-drive system is more of an on-demand 4wd, not a permanent AWD system like the quattro, I put it and the later 4matic system far below a real permanent AWD system for driving in severe conditions or for driving the car hard (and why else would you buy a Mercedes 4matic?). Other than from a stop, it is only AWD when the system senses wheel-slip, which for me was always too late as a slide has already started. I'd prefer good tires and RWD or if you really need AWD, buy a quattro et al without the electronic after-the-fact AWD system. Decent IMO for mild drivng and getting un-stuck but not worth it for the complexity and expense of maintaining it.