the transmission in my 85 is on its way out. its making a moaning sound, and the shifter gets stiff after driving more than 15 minutes.

i have an 81 gsl parts car that i plan on pulling the trans and rear end out of to swap over, and ill probably try rebuilding the trans out of the 85 for a back up.

the questions are, how long do the lsd's last? and is there a way to tell if this trans is bad without really driving the car? it shifts up to 3rd fine, and doesn't make any noise at low speeds, but the car wont go faster than 25 mph because of a dead rotor, or carb issues, so i cant really test the trans out.

i know swapping trans isn't that hard, but i don't want to waste my time swapping in a bad trans. i have done that before and it sucked lol.

 

I'm new here,but my advise when doing a manual trans is just take the case off and inspect the gears and synchros. Basically look for any worn or abused teeth on them. Excess metal shavings are a bad sign as well. As far as the rear end is concerned,I don't believe there is a problem swapping it,but I think the '85 has a "big" rear end and the '81 has a "small"one. The LSD's last a while too,but if you are going through the trouble of doing all of the swapping,you might as well take the extra time and rebuild the diff too. My '85 has a small one in it. I wish mine had the larger rear,because I would just swap in GSL-SE guts into it and go with the SE front suspension and brakes as well. Hope this helps.