[Mike C5.]

Paul, unfortunately parts replacement is really not feasible unless you have some special tools, an oven (to heat up the aluminum case to remove and install bearing races), etc. It wouldn't hurt to put in a sythetic lube as suggested above but ultimately, there's nothing more you can do other than avoid drag racing-type starts. The ring & pinion gear set alone costs around $500. Most people source a good used transaxle when the time comes. They are readily available since large numbers of 944 were built between 83 and 87. Good luck.