My stock 82 GSL will sometime drive just fine but most of the time there is a whining noise at 3500 rpms in first and second gear. I changed the oil last month and the tranny oil on monday. the engine can rev up to 4000 rpms just fine with no whine but bogs down a little and whines. any information helps. thanks. Dane.

random question: will the tranny oil that i used (75w90) work in my diff?

 

Dane,

Yes, the tranny oil will work in the diff too.

If the whine goes away completely in 4th gear at all RPM's, then it's just likely to be the age of your transmission, and the only way to really solve it is to buy a new/used/different transmission, or get yours rebuilt. If it is only at that specific RPM, it can still be your transmission, but I'm not exactly sure how to solve it without rebuilding it.

HTH