My M-21 muncie transmission hasnt been in a car for about 20 years. It was originally in a corvette that got rolled over and i then purchased the tranny a couple years ago. I opened the case up and didnt find any metal or chips in the gears. Should i rebuild it or not. I dont think there were to many miles on it. Im tryin to put the car together somewhat cheap and dont want to rebuild it if its not necassary.

Thanks.

If it shifts good, and does not make any strange noises....run it! No need to "fix" something that is not broken.
Just run a good quality gear oil in it....

My M-21 muncie transmission hasnt been in a car for about 20 years. It was originally in a corvette that got rolled over and i then purchased the tranny a couple years ago. I opened the case up and didnt find any metal or chips in the gears. Should i rebuild it or not. I dont think there were to many miles on it. Im tryin to put the car together somewhat cheap and dont want to rebuild it if its not necassary.

Thanks.

I agree, seal it back up. no silicone please, and use it. Use a GL4 lube or the stuff that Amsoil has that is formulated for the brass in the older transmissions. GM sells the right stuff, Pennzoil also has GL4.