I have a ht4100 '82 deville. I changed the fuel pump and replaced a bad brake line and so I finally got a decent "test drive" out of my car. I took it around the block and it had zero problems shifting. When I got home, I went to reverse up the driveway and I noticed reverse gear was slipping. (high RPMs but slow movement). But still all other gears work fine...
Any suggestions? Both transmission and engine were rebuilt before I bought the car. (within the past 12 years. Car has only been driven 10k miles in the past 10 years though...)
Any ideas? Fluid looks nice and red too and not burnt.