So I just replaced the front pump on the transmission 700r4. 1985 trans am. Forward gears worked fine but when I went to back up out of the parking space nothing. I can feel it go into gear or at least I think I can. But then it locks up and doesn't move. Maybe my rear calipers are locked up?

 

Did you disturb them while changing out the pump? Then, probably not. The calipers in that disc system can't "lock up" anything even when they're working as well as they ever do, especially not in reverse.

What does this mean? Does it mean that nothing happens when you shift it into R and give it gas except the engine revs up as much as it feels like? Does it mean that you can feel the engine load up and the RPMs won't exceed the converter stall speed (1700 RPM or so for a stock one)? Does it mean that when you put it in R you can't move the car at all, even pushing or towing it (which would be consistent with it being in 2 gears at the same time)? Or maybe some combination of the 3?

In any of those scenarios, the transmission is fornicated. You did something wrong while changing out the pump. If I were to guess, I'd guess the pump gasket isn't in right, or (more likely I think) one of the sealing rings on the pump is narfed. Go back and check your work. Which is kinda the first rule of something being farkled right after you work on it, in any/all situations.

 

Ugh, Have a feeling you cut the teflon seals on the pump shaft when installing the pump. Those 2 bigger teflon seals are for reverse. They can be a pain to install correctly. Good luck.

 

I am just posting so I can keep track of this thread.