Okay, Short history Ill try to keep it short. I keep blowing/going through transmissions. The 2 4l60s they were crap... So I did a 4l80e swap. Much better tranny, but this is not what this thread is about.

Im on my 2nd 80e, and purchased a new 3rd 80e back last year, that I had not have the chance to install it yet. All because my 2nd 80e tranny lost reverse, and slips. Like the other 80e before its place.

The 1st 4l80e tranny never had reverse from day 1 of the install, and slipped a good bit in the middle of the rpm range. And would kick out of OD on the HWY.

SO I Removed it & Switched it out for my 2nd 4l80e tranny which worked flawlessly for about 1 week after the install. Then that #2 80e tranny I had too much fun doing a 7 block burn out. The next morning NO reverse at all. The engine would just rev in reverse. It would even try to pull forward in Neutral as well as Park! When I put it in Park it would hit lock and JAM and shake the entire truck as If I slammed it in park while driving. The truck would not even roll or push in Neutral.

So the 2nd 80e is what is still in my truck, and I still drive the truck, just no reverse, and seems to be slipping randomly, but it still always pull or tow. Heck it will still roast the tires even. When I say slipping, I mean alot extra foot pedal is needed to get going.

Yesterday, I get in my truck, and noticed for about 2weeks-1month ago, that it would actually roll back in Neutral while the engine is on, which is something I could not do before, as it will drive forward in Neutral. Said what the heck, put the truck in Reverse for the kicks of it... Low and Behold. She backed up and even did a burnout in reverse. Now the tranny feels like its not slipping at all anymore. 1-2 shift is hard and now it has developed like a ultra hard shudder between 1-2 shift, especially if Im driving slow, and back out the throttle. NOW Im noticing it to shudder at the end of 1st before 2nd. It will jar the entire truck makes the windows blurry.

How can a tranny be dead, and then start working perfectly again?? besides the random heavy shudder, if Im driving lightly 1-2shift. Why would I even loose a gear and it come back working?

I still have a new 4l80e but Im starting to think the 1 inside the truck is still good.....

 

If im not mistaking your pcm or tcm may need to teach its self how to shift in gears. Or the neutral shitch not in its correct spot

 

Sounds like worn forward clutches that welded themselves to the steels and broke loose which is why you now have reverse. The clutches and steels are roasted.

 

It is in the correct spot, I removed, it and turned it several times by hand. heck even rewired it and added a new style switch.. It is NOT the problem... except for my reverse lights not coming on now, cause I need to replace the switch again with the old style I had before.

2 different Trans techs told me that my clutches are welded... So I do believe that part. This sorta makes some sense, so after they got welded they got broke loose after 6 months>??

Still why does it not even slip anymore, and it drives perfect now, even stays locked in OD, instead of slipping out like it did before.

I would keep it how it is, if I can get rid of a heavy shudder I have at low mph randomly.

 

My current 2nd 4l80e tranny that is still in the truck, it is not slipping like it was before!! I actually can use less pedal and go faster, Truck just runs so much better now that the tranny is acting right. WTF gives.

 

Make sure to update this thread in a few more road tests when its back the way it was when you parked it!

 

Sounds like you like to do a lot of burnouts

 

IMO its still riding like 31k miles that was in it. Have the tittle to match the vin.

I think my problems might be PCM related. I have a 3rd backup just in case. That's why I'm stunned. Might need a new coil pack or something.

 

Stupid question but you've checked the fluid level right?

 

I think you have a PCM or a Wireing issue. The Neutral Safety/Gear selector switch may also not be located properly as well.

You did not mention what you did as far as the conversion goes for the wiring.

Also were are you getting the transmissions from??? Used or Rebuilt???