JHC928

I am considering the purchase of a 1981 Porsche 928 with the 3 speed MB transmission. The original transmission required replacement 2 years ago at about 120,000 miles due to excessive slipping. A Porsche shop swapped it out for an identical used one. Since then, the vehicle is reported to be operating properly.

Is this a "red flag" that might portend other major problems? Or is it more likely that regular maintenance of the original transmission had been deferred? I had understood that these MB transmissions were quite robust and the failure worries me.

C531XHO

My 81 3 speed slipped after I serviced it. Not enough fluid. I have heard of issues caused by old/burnt fluid which might be fixed with fluid and filter change. Trans are heavily built. Originally fitted to the Mercedes w126 of the era. Widely available used, I wouldn't worry too much
David

Shawn Stanford

Nope. Not only are these transmissions robust, but this is an old car and the various systems are isolated. There's a torque tube going into the transaxle, a couple of fluid cooler lines, the gear selector, and a couple vacuum lines and that's about it. Very simple stuff. I wouldn't think twice about it.

The Forgotten On

It's fine. The original trans was probably not as well cared for as it should have been or was just getting old and the seals all dried out.

It's a common issue with all older cars and the only fix is a rebuild or replacement. Don't worry about it.