Yukon04

iTrader: (5)

I have well over 1500 in parts and converter sitting in a 4l80e I installed on my Yukon after thinking I rebuilt it correctly myself well something is wrong. Seems like reverse isn't present, drive barely moves, 1st works and seems to engage the tc then when slowing down it will stall the engine out. Not sure what to do now any advice?

Suburbazine

I haven't known anyone to have their first, second, third or fourth self-rebuilds work properly. It's a learning curve for sure. I'd say tear it down again and see if you missed check ***** in the valve body.

Ferocity02

iTrader: (59)

Ah don't say that! I'm rebuilding one right now, taking my sweetass time. It's pretty straightforward but definitely a lot of places to make a mistake or forget something.

I rebuilt the T56 I'm using now and it's been working great! But it was far simpler than an auto.

1FastBrick

iTrader: (17)

Did you do the relay mod with a 60 tune or did you get a segment swap???

Did you rebuild the pump or have it inspected???

How about telling us more about what you put into the unit you built???

Ferocity02

iTrader: (59)

Any codes?

Yukon04

iTrader: (5)

No codes, no reverse, when in drive takes a ton of effort to barely move, dual feed mod, red eagle clutches and bands, transgo shift kit, had a wiring adapter and PCM flash performed. Abs is disabled via fuse pull. Pump was in good shape convert is a new build one 2800 stall, modded the tiny hole on pump all end plays and shaft play was measured correct, problem still occurs when electronics are unplugged, and lastly put truck in 1st converter locks when you move and will bog engine down or knock it off when hitting the brakes.

Ferocity02

iTrader: (59)

Try measuring the pressure with the little port of the driver's side.

Vortec350ss

iTrader: (20)

Yea measuring pressure would be your first clue... I'm dealing with some tranny issues myself after an HD2 install. Its really disheartening.

Yukon04

iTrader: (5)

I feel like it has to do with the reverse pin and the garbage kit I was sold seems like it doesn't apply enough

TechGM

I would yank it out again. From what I've seen an incorrect build on a 4L80 will last only a couple times before it starts taking out some of that 1500 in parts you've invested. Just take it all the way down to your center support assembly and start inspecting. Make sure all your housings are fully seated, air check clutch setups, and recheck. Go through valve body and make sure valves move freely. Check valves in pump to make sure none are sticking there also. I've seen that valve stick causing it to feel like TCC apply in 1st. Good luck