gesto

4L60 was supposedly rebuilt about 20k miles ago and 2800 stall and cooler per the previous owner. No previous trouble with the trans for the past year with 50+ passes. Fluid and filter were clean and full. Second pass of the night without nitrous and a short cool down. Idling to the staging lanes the rpms would raise and lower and sounded a little like a slow loping cam. Must have been slipping.

Launched normally and 1-2 shift was normal and had a slightly better 60' than usual. Right after the 2-3 shift I heard a bang and then no gears, just free revved. No smoke or fluid. Engine runs fine but there is a loud whirring noise from the trans.

I tried to search but couldn't find anything on point. Any guess at what broke? From my reading it might be the drum????

I ordered a Performabuilt Level 2, new cooler, FTI 4000 converter, and SFI flexplate. Also replacing rear seal. Am I missing anything? Goal is only 11.50's.

Should the radiator be flushed, or should it just be bypassed?

Thanks!

mrvedit

From your description a broken input shaft/drum is a likely possibility.
If you have Reverse, then a broken forward sprag is another possibility.
Assuming one of these, their might be loose metal circulating in the fluid; in this case the cooling lines need to be flushed, but if you have a multi-path stacked cooler, you might want to replace that to be sure.
A level-3 PerformaBuilt should be able to handle your needs; you might ask about having the Sonnax HD 2-3 shift valve installed and how you should then race in D3.

gesto

Thanks! No reverse. I guess the diagnosis doesn't matter much since I've already ordered a replacement. I've purchased a new cooler and lines and will trash the old cooler and lines.

Should the radiator be bypassed or flushed?

The guy at Performabuilt spec'd a Level 2 so that's what I ordered. Looks like it does not come with the Sonnax HD 2-3 valve. They claim it will support 700 HP and I don't plan on more than 400 - 450 RWHP for the next couple of years. I hope I didn't order too weak of a trans. If it doesn't hold I'll just go TH400.

Automatic transmissions are magic mystery boxes to me. Thanks again.

98CayenneT/A

Bypass the stock cooler in the radiator and run a nice big stacker style cooler.

gesto

http://ftiperformance.com/Complete-T...M7B-FTCPKG.htm

This is the cooler package I ordered. If it's big enough I'll bypass the radiator. I don't want any trash in the new transmission. I'm also going to have a bung welded to the pan and a trans fluid temp gauge added.

I would have gone TH400 but I kept reading it will slow the car down at this level.

AnotherWs6

iTrader: (17)

Performabuilt requires that you bypass your radiator AND flush your lines or your warranty is voided.

I bought two cans of this.......


Only ended up using one. Worked well. Would def recommend. And take pictures while you do it.

gesto

Thanks! I will bypass the radiator and the new cooler kit is supposed to come with new lines and fittings. Hopefully the old lines won't be needed. PB is supposed to include an aerosol can of cleaner but I will pick up a couple of cans just in case.

I hope the bellhousing isn't hard to swap.

PBA

To keep from replacing everything here. Install a large transmission filter (engine type of filter) in the top line going back to the transmission. This will pick up any metal that is coming back to the transmission. If the filter bracket has a bypass, make sure you block it off. I have recommended this many times over the years without any problems. This will solve the contamination problem, and save you money and labor here.

gesto

Good idea!