Transmission rebuild or upgrade?
 

Greetings all,

I have an 84 with the 915 transmission. The shifting is gradually becomming more difficult and I will be rebuilding the linkage soon.

If that is not the problem I may need to rebuild the transmission. How difficult is it for a backyard mechanic to rebuild the 915?

Is it a good idea to upgrade to a G50?

Is the G50 the same in how it mounts to the car and the engine?

Thanks, Darryl

I am in a similar situation with my '83 SC project car. I would be interested in posts on this topic as well. I am currently looking at a G50 from an '89 Carerra.

Do a search using "915"; there's a lot of information on this topic on the board. Yes, you can rebuild your transmission but I would recommend you do it indoors and not in the backyard :D. Plan on spending around $600 to $800 on parts. Jim

And multiply that figure by 5 to 10 to install a G50. It's a better transaxle, but it is not a bolt-on mod by any means.

In terms of upgrading, you'll be better of rebuilding the 915 and adding a Wevo Internal Gateshift. The Wevo part is $895 but it makes the 915 shift much better than a G50 even.

If you need to ask about the difficulty of rebuilding a 915 then the G50 swap is way out of your league, meaning as Jack pointed out BIG bucks and major surgery to the car and or transmission.

rebuild the 915

The G50 is wider, so the torsion tubes need to be moved out. That's why the spring plates on 87-89s stick out so much more. You can also get a narrower G50, but, as mentioned, that's big bucks.

A nice 915 is not a bad thing.

Chris.

I did the G50 upgrade in my car. It was a little more expensive than I thought it would be. It was also more work than I thought mostly because I had to move the motor also. That was time consumeing. Am I glad I did it? Yep. Would I do it again? You bet. But I always say that.:D

I just rebuilt mine and it is a piece of cake. Much easier than my RX-7 or my son's Nissan. If you read these two posts you'll be all set.
http://www.pelicanparts.com/MotorCity/marcesq3/TrannyRebuild.htm
and
http://forums.pelicanparts.com/showthread.php?s=&threadid=138132&perpage=20&highl ight=flywheel&pagenumber=1

The only "special" tools you need are a 27mm socket, 36mm socket and an old clutch disk to hold the input shaft for the retorque.

Don't open the case with it vertical or the backup light plunger falls deep into the tranny and gets hidden and stuck by the residual gear oil.

Thanks for the advice, all. I did find a bunch of posts on the difficulty of upgrading to a G50. This brings a few questions to my mind: Is it worth it if I plan on tracking the car (PCA and SCCA events)? Is the 915 going to hold up to the increased punishment as well as the G50?
-Ed

There are some gotchas in the tranny rebuild, but it's fairly straight forward. I finished mine last weekend and the only extra stuff I needed was a machine shop to press out the input shaft bearing and to fabricate a 41mm 12" deep socket. I think your average shade-tree mechanic could do it with some online support :)

You have to have the 915 if you plan to race your car in PCA stock class. It's a great transmission if it's properly rebuilt and everything's adjusted correctly.

If you want to update your '84 to '87 Carrera specs in all respects, including cutting out the torsion bar tube and welding in the one from the G50 cars, the rules allow it.

But many, many, many races have been won with the 915 (and the 901 for that matter). A ham-fisted driver can kill a G50 just as easily as a 901-- it's more operator technique than limitation of the box. There are a bunch of fine modifications for the 915 that bring it up to competition standards, not cheap, but certainly cheaper than a G50 upgrade. A search for shift gates, for example, brings up a few interesting mods.

I think it's an '83 SC so he can't change it. I never had any issues at all with the 915 in my G class car (78SC) and it had no gate shift or any other mods. Like John says, it's about how you shift. The guy who bought my car is doing the Wevo setup & I'd love to see how that works out. I also think the Seine gateshift looks interesting.