I've got a '86 base(NA) with a 5 speed. Will a '89 (NA) trans fit in my car? Is it exactly the same or will I have to do some swapping of parts?

 

You should not do this even if you do it correctly. here is why.
the 89 tranny will bolt up just fine. BUT
you will have to change the flywheel and its counterweight(and get a different clutch)
since you changed the rear counterweight on a series 4 engine with a series 5, you will have to swap out the front counterweight on the fron t of the engine

even when you do all that, your car will never run correctly as wrong as you have different counterweights. The 86-88 engines have a different balance and counterweights than the 89-91 engines.

When you change the counterweights your engine balance will be WAY off, meaning your engine will run like crap and possibly lead to a premature death.

 

I dont think your correct, a friend of mine swapped an 89 into his and didnt have to change anything. The counterweights dont have to be changed b/c your not changing anything in the engine, both 86-88 and 89+ use the same size clutch, so thats all that should matter...I'm pretty sure...

 

Bigwoogle is incorrect, the flywheel must match the ENGINE, not the trans.

You're good to go, swap the 86 for the 89 NA trans, no problems. No advantages, but no problems.

PaulC

 

No the flywheel on the 89+ is different with a different size counterweight, when you change out the rear counterweight with something other than stock you have to change the front counterweights. And being as how the rotors in an 89+ are lighter than 86-88, changing the counterweights throws off the engine balance. You have to change the flywheel for an 89+ tranny

 

Everything you said is correct, except you need to replace Engine for Tranny.

Yes, the rotors are a different weight in an 89 vs 88. Yes, the flywheel (and thus the counterweight) is different 89 vs 88. However, the flywheel has to match the ENGINE, not the tranny.

Otherwise, you'd put a flywheel that's made for an engine with lighter rotors on an 86 block, and end up scattering the motor.

So. Repeat after me.

Flywheel matches engine. Flywheel does not need to match tranny. Before you reply and tell me I'm wrong, read what you just wrote. And think about it.

PaulC

 

Or just read this:

I used an '86 tranny in my '90 for several years without any problems. The only thing that was changed was the tranny.

 

Correct!
As long as the flywheel matches the engine and the trans bolts up to it, everything should be fine. I could even bolt up a transmission from a Camaro if I had an adapter plate to match it up to the engine and make it work. (would probably require special clutch, pilot bearing etc.)

I would not however have to change anything on the engine or flywheel as far as balancing is concerned.
Oh, BTW, I have done this with other engines and have never had a problem with engine balancing.
Hope this helps!