How to diagnose rear end differential failure 1967 W108 250S

[karshack]

Hi all,

My mechanic says I am suffering from a failure in the rear end. Engine turns on, 4spd manual engages gears, speedo responds when in forward gears, and drive shaft (propeller) turns. But the wheels do not turn at all.

Unfortunately my mechanic does not do tranny/differential work. Its a 1967 250S W108 4spd manual on the floor. The differential case is stamped 092097 4,08. The places that he usually farms this sort of work to did not want to touch it because the car is so old and they did not want to get into a "waiting for parts" circus.

So, how can I go about diagnosing this so that I can have enough knowledge to make a decision to repair myself or sell the car? I see that the rear ends on ebay right now are all of the drum brake variety. I really don't want to make that sort of change; though I am willing to go the route of the 3.27 gear ratio.

If I could just know how to find out what is wrong, I would know where I stand (other than the bus stop).

Thanks in advance.

ps: I forgot to mention that the driveshaft appears to be rotating the pinion gear just fine. Something wrong is happening somewhere inside the pineapple - I think. This has been my daily driver. Hopefully to resume before the rainy season.