I'm running a 700R4 with a Hughes 3000 lock up stall speed converter. My engine makes 467/517 at the flywheel. In my data logs I see the converter really flashes to about 4300 at WOT. My tranny wasn't really build for this HP when I had it rebuild 10 years ago or 5000 miles ago. Anyway I think the tranny is starting to go. It drives fine around town, I can't even tell it has a stall converter at low RPMs being it seems locked all the time until I punch it. It's just on some WOT pulls its will just over rev and not shift from 2-3. Sometimes if i'm doing like 50 mph and then go wot and it down shifts it will seem to just free rev with out making the car pull. Thinking the tranny bands are going bad.. So I have 2 questions.

1.) Do you guys think the tranny is going bad being it just wasn't built for the HP of the engine the car now has??

2.) Do you guys think its going bad being I have a larger stall converter but no large aftermarket tranny cooler? It is a lock up converter and seems locked even at low RPMs until I jump on it.

 

Needs rebuilt for your power level asap. A trans cooler is always a good idea.

 

Anything higher than stock stall should be using an aftermarket cooler.

 

So these slips in the tranny are intermittent, and tend to happen after a few wot pulls. Think the the damage is done or if I installed a tranny cooler it might stop it from happening?

 

1st slip, its done.

 

The damage is done already. The higher the stall, the higher the temp is creates. It makes sense that after a few pulls it slips because the fluid is probably in the middle 200's for temp and that is way to warm and the fluid breaks down. Definitely need a cooler for the next time.

 

The fluid won't break down at those temps once it hits mid to upper 200s then the tranny is killing itself. Generally speaking most trannys will run right around 180*-200*.