Took the truck to the local 1/8 yesterday for it's first passes since I rebuilt the 4L80 after the converter clutch took a dump. For the rebuild, I basicly just dissassembled, cleaned, changed the seals and reassembled as the frictions looked brand new and none of the hard parts or bushings showed any signs of wear. At part throttle everything shifts snappingly. At WOT the 1-2 shift takes about two seconds to fully engauge. After this happening on the first two passes, I maxed the base shift pressure table at 96 from 320+ with no change. Fluid was in the upper 1/4 of the hash marks on the dipstick and I added another half quart after the third pass putting it just above the hashed area, again no change. Second gear held great for the burnout, just slips on the 1-2 at wot.
I plan on dropping the pan sometime this week to check for clutch material from the converter (very parinoid). Is there anything specific I should look for on the valve body while it is off? Anything tunning specific? I am really hoping I dont have to drop the tranny and go thru it again.

 

Damn, that sucks! Wish I could help...What converter did you have?

 

probably a p.i!

 

You could put 25% to 30% of your tranny torque management back in for a quick fix. I had to do this on my 08 4l65 to keep it from slipping on the 1-2 shift with no shift kit.

 

If you slipping at WOT on the shifts i would think ACCUM issue or inadequate line rise i would get a presure reading at max and see what it is

 

Hope you get it figured out Kenny. I'm waiting on some good times when you get everything sorted out.