Hello:
I have the exact same problem with my '91 4x4 Loyale Sedan (normally-aspirated). The slippage is only in the higher gears, and at lower, winter temps. Recently, however, there is some kind of smell coming out of the engine bay and I am not sure what it is. It smells like brake lining, but I can't hear any scraping sound when I listen to the car on the road. Could the clutch be going out? Maybe one of you guys can tell me.
Regards
Bert V