Had a buddy of mine rebuild the 80e in his 05 2500 because it finally quit pulling it self in drive. But it did have reverse just fine. He tore it all the way down and found the forward clutch packs completely smoke but everything else looked great. He ordered a master over haul kit and new bonded pistons. Everything went together just fine and air pressure test good on the two packa that you can test with a blow gun. He also installed a transgo shift kit. Just the simple one not the hd kit. Anyways long story short he gets it all together we put it back in the truck and it wont pull it self in forward or reverse now. Had just reverse before rebuild. With the truck on the hoist it will shift fine through the gears. But when you put it on the ground it wont move. All the pressures check out just fine. Unplug the connector it defaults to max pressure. We have tried 2 convertors a brand new one and the old one. Does anyone have any ideas??????

 

Also, did you run tests on the valve body? Resistance checks, look at valves..

 

Resistance checks on the solenoids??? No we have not. It shifts perfectly fine up on the hoist. And you can watch data on the tech 2 all seems to be correct and no codes. I guess I should say it will barely move. If you let it idle in low range on the transfer case or barely any throttle it will move but just anything more than just layn your foot on the gas it starts it revs up and starts to squeal/whine.

 

You're leaking pressure somewhere.

 

Leaking pressure that wouldnt show up on a gauge?

 

Any other ideas?

 

The overdrive sprag? If installed upside down or improperly, it will do what you're describing. Try putting it in manual 3 and see if it moves better.