Hello, hoping someone can offer some guidance: I have a 4l80e that's been dual fed and has many of the usual mods. It's been running well for some time but has lived a hard life, boosted 4x4 launches, towing, overheated a few times while towing over long passes.

It's been running fine then today as it went into 2nd at partial throttle it started dragging noticeably - enough to actually slow the truck until it shifts back to 1st and everything feels normal again. If I put it manually into 2nd from a stop it will roll a few feet until it binds and holds the truck in place. It didn't lock the tires up or anything violent, it's just a smooth binding that the engine can't power through. I stalled it up while in 2nd to see if I could get it to move and I saw a puff of smoke and could smell ATF. I hobbled it home after that, holding it in 1st where it drove normally.

I plan to remove it and go through it this weekend but honestly don't have an idea what to expect. If anyone has experienced this or has an idea where the problem might be, I'd appreciate the insight. Even a guess would be appreciated as I need the truck to tow this Sunday and don't think I'll be able to have it out until Saturday. The parts store isn't open on the weekend so I'll need to guess at what to buy this Friday.

 

My best guess would be the low roller is locked down. It holds in 1st so no problem but is not supposed to hold in 2nd
https://s32667.pcdn.co/wp-content/up...rceTips_06.jpg

 

Hi Frank, thanks for chiming in. A piece of the front planetary came apart and wedged trash in the low roller. You were absolutely correct with your diagnosis.

 

Your welcome.