Jason,

Hows it looking for ECR? You got a spare sourced yet?

Ryan

I found a gearbox out of an 83 down in Houston for $250. I dont think itll last long, but it should get me through the week end. I found another one in Alvarado that may be a good candidate to put some money in. Id like to put the LSD and short 5th out of my cratered trans into a good used one as well as pay a shop to replace all the bearings in. That should give me a gearbox that will last at least a couple of seasons. Maybe by then we will have figured out a better way to make these things last.

Nobody thinks that a cooler will help things? Is the pinion gear not submersed in oil when filled properly? If not, does it rely on the ring gear rotating in the wet sump to supply it with oil?

I put a an oil temp gauge in my trans last night. We'll see what we find this weekend in the endurance race, which will again be on the new RR's. BTW, I haven't blown a trans in 6 seasons of racing, and 4 seasons of endurance racing, though I have switched cars over the years. I'm not saying it doesn't happen, but it's not inevitable. I have gone through a lot more axles, but the new inexpensive option for EMPI axles for the Vanagon should help that - no need for used or rebuilt axles at that price.

As far as the R&P, we do share this trans with Audi models. Maybe there is a cheaper Audi option with the same R&P?

I have always found that the 944s were pretty resistant to shock loading on the trannys due to the built in shock absorbtion of the system. The long torque tube is like a long torsion bar that twists a bit under strong engine load (clutch drops for example). 911s, Boxsters, 914s etc... are not so lucky and I have broken plenty gearboxes in them.

Temperature is a factor since when they get hot the tolerances tighten up and you start losing lubrication. Why, because as the tolerances tighten it pushes out the oil layer between the R&P. Once that happens the mechanical heat is no longer transferred to the oil but held in the gear. Because of the surface area of the Pinion being so small it gets hotter faster and fails first. Gearbox oil temperature measurement is important but will not show the dramatic localized temperature of the pinion when it gets to this point. One solution besides additional cooling and R&P mesh point spot oiling is simply open up the pattern (loosen the R&P). The downside to opening up the gap is you will get more wear and can hurt them if you drop the clutch before it is up to temperature. However once up to race tremps which are much higher than street temps, you will still have a reasonable gap and maintain an oil layer.

Last point here is the dry-sump effect of using a tranny pump and cooler. When you have a wet sump gearbox you have the same issues as with a wet sump engine oil pan. The ring gear pulls the oil up and froths and aerates the oil as it does so. Aerated oil does not lubricate or cool as well as pure oil. Plus the oil is splashing all over the place vs. going where it is needed most. You will find an oil cooler on my gearbox from race one and unless rules dictate otherwise I will be spraying the return oil directly into the R&P mesh point. You will not be seeing me on my back changing out a tranny at any events I can assure you.

The CVs and axles are always going to be a weak spot since we cant upgrade them. On the big HP 944/911 cars I would run tri-pod CVs with ChMo axles to keep them reliable for endurance racing. But Like Doc said they are cheap enough that they are turning into disposable items anyway.

I haven't seen or heard of one trans failure in our region and haven't seen much discussion about them here either. I have one spare in the parts car and one broken one that came with my car because the kid who owned it did burnouts and did break the ring gear, and I don't even think about bringing a spare with me. I don't think it's much of an issue with such a low hp car, even with high heat, speed shifts, and curb hopping. Just don't do burnouts and you'll be fine!

I agree, I have been around a lot of 944 race cars and NEVER seen a ring and pinion failure. I've seen some trans failures but mostly worn synchros/dogs/gears from rushed shifting. I had to change mine out last year when it would no longer engage 3rd. Luckily you can find used transaxles everywhere and it isn't that hard to swap a limited slip into a good open diff trans.

I do carry a spare in the trailer so you're covered Ron

The cooler is NOT legal currently.