69CapriceHDTP

Have a 6.0 with an S475 only at 500rwhp at the moment. I got about 5 dyno pulls and 10-20 miles on the freshly rebuilt 4L80 which was built by a reputable guy that builds lots of race transmissions. Has an FTI converter and the drive gear ground itself into the pump and wiped out the whole transmission. I sent the converter off to FTI to check it out and had the entire transmission gone through again. FTI claims the converter is fine after cutting it open, inspecting and measuring everything. I put it all back together and took it for a 10 mile drive and put it back up on the hoist. I dropped a little trans fluid and its got metal shavings in it already. The converter slides roughly 1/4" out of trans and I noticed it bottomed out on the flex plate bolts (stock 6.0 flexplate with shim) and pulled maybe 1/8" on the flexplate. Never noticed this before but FTI claims I got same converter back. They told me it can only slide out of trans 1/8" and the rest must be shimmed and that could be causing the issue. I pulled engine out of car and tore it down to inspect Thrust bearing on crank and that is in perfect shape so the crank is not walking either. Any help would be appreciated. Thanks!!!

truckdoug

iTrader: (25)

pull the front pump and make sure the gears are in there correctly. a bone stock junkyard 4l80e can take that much power

tfi racing

iTrader: (2)

You should move this to the auto trans section of the forum,lots of guys there that know their stuff and great with giving advice.

ewingr

Has this been running before? You know that the programming of the PCM is correct?

I had a 4L60e get fubarred due to bad programming. I had told the PCM programmer my engine was a Corvette LS1, and the transmission was a 4L60e, in a '56 Chevy. He took that to mean it was a Corvette setup...ie a 56 body dropped on a Corvette carriage. Not.

Blew the transmission in about 50 miles. But...there was something obviously wrong when driving.

69CapriceHDTP

Harness was changed over to 4L80 and the tuner says he changed the programming in the computer because it was wrong yet. Very reputable tuner so I don't imagine that's the problem, but at the moment were at a loss for ideas. I know a junkyard trans will handle this, we just have no idea why this is happening. I did make a thread in the trans section, I'm not on here much and didn't realize there was one.

alocker

iTrader: (10)

Did you flush the cooler lines before the new trans went back in? That could be your source of metal. Are you sure you have the correct flexplate for a 4L80e?

Jimbo1367

That^^^^^^^^^^

svslow

Converter could not be engaging fully into the pump.

JoeNova

I vote converter not seating properly.

I'm putting almost 300whp more than that through a 150k miles junkyard 4L80e.

hellbents10

iTrader: (10)

Either converter spacing or torque delivered sig is not accurate from fudged ve and injector data for a 2-3bar OS.

jimmyg

Converter to flywheel needs to be shimmed . When you tighten tc bolts it pulls it too far out of trans .
Also what do you mean by shim? Are you running a crank spacer? . It should have a crank spacer unless it's a real early 6.0 with a long crank flange