4l80e

Hi guys. Hopefully someone can give me a lead on what I need to check. I have a '99 cc Chevy with a 6.5/4l80e. Friday coasting down to 25mph, I heard a loud bang and screeching noise from my truck. It only lasted a couple seconds, then my truck felt like I was riding the front brakes hard. I shifted to neutral and the truck kept coasting like nothing was wrong. When I shifted back to od, felt like I was on the brakes again. Down shifted to 3rd and truck rolled fine. I have 1,2,3, but od feels like I'm on the brakes while driving. Truck is making plenty of boost, but when it hits 4th it has to boost higher to maintain a constant speed than it does in 3rd. There is no more noise from the trans beside the one time it did it on Friday. Is this my torque converter, pump, or do I need a whole new trans?

my understand is 4th gear/od are common to fry out in these trannys pretty frequently. mine started slipping in 4th and i asked a buddy who works on em. he said that they fuck up 4th more frequently than others. thats what it sounds like happened with yours. a company called transtar sells kits for about $400 bucks and if you have a basic knowledge and feel comfortable you can purchase the rebuild manual for it for another $100. im putting off since i really dont use 4th often and i dont have a whole lot of time to have my truck down. i will just buy a junk yard tranny, flush it, and install. then ill rebuild the old one. that way i have a spare tranny. did the same thing when i blew the motor.

Thanks desert. I've been thinking of getting a junkyard tranny and doing the same thing. Never pulled a trans apart, but built lots of motors. Guess its time to learn to do a trans.

if you can tear an engine apart these will be not that difficult for you. i suggest getting the manual and using that. those parts kits are what a lot of tranny shops use, and i work for a diesel heavy duty truck shop and we will convert to those kits. i would do the junkyard route and rebuild the one that is in there due to the problems that these trucks have with the 4l80e's.

I strongly suggest replacing all the electrical components, and the entire wiring harness along with the rebuild. I just got done with a rebuild on mine, if I hadn't thought to check on the wiring, and have all the electrical parts replaced, my newly rebuilt transmission wouldn't work and I'd still be trying to fix it instead of driving it.

I had planned on replacing all the solenoids and harness while I'm in there. Its a small investment compared to the amount if time to pull the pan back off and replaced e them under the truck. Now I'm just looking for a suitable replacement trans to buy so I can have the truck running while I try my hand at rebuilding this beast.