Race car transmission fun... lots of pics

[RedLS1GTO]

As most of you know, I have a new track car for the upcoming season, as ex-ASA series Monte Carlo converted to road race warrior in SCCA’s GTA class. I figured I'd post this up because I'm bored. We have a lot of DIYers here who might find it interesting... if not, piss off. The main issue that I have had is with a leaking transmission. It’s an older style magnesium case Jerico dog ring 4 speed that was most likely originally out of a late 90s/early 2000s car in 1 of the NASCAR series. This is the 3rd attempt to fix this damned thing. Initially it appeared to be the bearing retainer leaking. This trans definitely sat for a while with fluid in it so some had seeped out of the input shaft seal as well. We pulled it apart, sealed it back up and put it back in. Looked good for all of about a day and then the familiar drip was back. We pulled it again, replaced the bearing retainer/seal assembly, resealed everything up and put it back in. An hour later… that f**king drip was back. Soooooo…. Out it came again. Rather than drag it back up to the shop in Cincy (I’m in Louisville) I decided to go at it in the garage. The best part about this thing is how easy it is to get to stuff. From the time I got it up in the air, the trans was out in about an hour, without rushing at all. The most difficult part is drilling out the rivets that hold the floor in place. After the first time, we figured out it was easier to pull the floor out and take the trans out with the shifter attached rather than to try to wiggle up there and pull the shifter off.

I need a bigger garage!





Floor gone… easier to go through the floor and pull it out whole than to try to get the shifter assembly off laying on my back.



Yep, that’s the exhaust.






It LOOKED like the leak was from the bottom of the bearing retainer… a common leak point.

But upon further inspection, it was actually from the cluster shaft sleeve. It's an aluminum sleeve pressed into a magnesium case.





Here’s what it looks like inside (not mine).



Jerico’s answer? You’re S.O.L. Buy a new case.

MY answer… f**k that. I can’t take credit for the idea, but this is the fix:

Dremel with a ball cutter. Cut a “trough” around the joint between the case and the sleeve.



I’m a surgeon with a Dremel.



Round 1 of JB Weld. Yup. JB.



After round 1 set, add layer 2 to fill it back out to flush:





While we’re at it, fix the f’ed up threads on the bearing retainer and top cover. Apparently the countless rebuilds have taken their toll over the years. Whoever invented helicoils... genius.





I’m heading to the Daytona 24 this weekend so it is going to have plenty of time to get good and set before I put fluid to it to see if it works. The trans shouldn't be under pressure so it doesn't have to be THAT strong... If not, it’s time for a new case.



…and if anybody wants to know what’s inside a road race Jerico, here ya go.

[mike100]

clunk clunk clunk. Rev matching helps, but the faster you shift, the less wear and tear on the dog rings.

I have a Spicer slip yoke that I tried to tig weld- same deal...leaks through a pin hole still- JB weld is better