4l80e problems calling all transmission experts
 

I've been trying to diagnose why the bushing and seal came out of my new built 4l80e. I've had a 4l80e in my truck for a couple years now and there were no problems at all. I did the swap with a used unit and it went out a couple months ago. I got it rebuilt with some upgraded parts.

Couple of weird things that happened just recently that may have caused it.
1. Transmission temps spiked way up randomly while I was going retry fast down the highway.

I turned it off and let it cool then drove home the rest of the way it only got over 200 degrees once after that. That day I took it to an exhaust shop because I wanted to get an O2 bung welded in and I had to fix an exhaust clamp that came off while I was going down the road.

2. When I was driving on the rack I'm pretty sure I bottomed out my y pipe on the rack and you can see that's where my transmission started leaking. When they got it up there I noticed a few things. My tail housing looked burnt. It was painted grey like my truck and the seal and bushing were just sitting on the yoke. Also when we took out the drive shaft the yoke look all scarred up like the bushing was eating into it and the bushing looks stretched out.

Any help or insight would be very appreciated! The transmission builder is sending me a whole new tail housing but I don't want this to happen again. Tired of messing with trannys lol

Driveshaft imbalance will cause that. How bad of a vibration do you have, especially at speed?
If you have a GoPro mount it underneath looking at the slipyoke where it goes into the housing and get some video.
There is a bushing and thrust washer in the back of the case that supports the output shaft. My concern with that would be that enough vibration to have worn away that much of the slipyoke bushing may also have worn out the tailshaft bushing in the case. Unfortunately that bushing is the very first thing that goes into the case before any other rotating components.
When the trans is supported on a jack to get the tailshaft housing off, try to have a look at the edge of that bushing. Also, there are several different types of 4L80-E tailshafts - please take a photo of that exposed tailshaft and a photo of the slipyoke separately so we can tell you if you have the right ones. (It's possible to put a short slipyoke onto a tailshaft intended for a bolt-on yoke but there is not enough spline support to keep the drive shaft aligned, etc.) Also want to see how much spline engagement you have with everything installed.
No promises... but photos will help

I put a new tail housing on it with a new bushing and seal and all it does is leak slowly out the seal...I put a new seal on it and tested it and all was good till I tried it again. I was looking at my yoke and it looks like when my other bushing came out it ate at my yoke so idk if fluid is slipping past the yoke or what so I have a new yoke coming in. The only thing else I could think of is driveshaft imbalance but I don't think that would just randomly happen. None of the weights came off either.