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The pump on my 4L80E failed the other night at the track and I don't know why, i'm hoping some of the experts here can chime in with suspected causes. You can see from the pics the smaller gear shattered. The pieces actually welded themselves to the pump cover, I had to knock them off with a hammer.
The bushing seized to the converter. It's an FTI triple disk and I sent it off to them today for a refresh, hopefully there's no internal damage.
The odd part for me is the filter material was blown out and ended up in the bottom of the pan. Not sure what happened there.
The rest of the trans looks fine, even the bushings look good. It let go at about 120 mph and blew quite a bit of fluid out the vent under the car.
No it wasn't a new install, it's been in the car for about 1 1/2 years. I just recently had it out to put in a D3 brake but it had proper clearance on the converter when I put it back in, had the pull the converter to the flexplate about 1/8 inch.
After going back and reviewing old data logs the pump may have been cracked for some time. The car developed a rattle I never could find around the end of March. I looked and looked but could never find it and looking back it was coming from the pump area. I just though it was something external rattling against the case.
Logs from before that and the ones from last weekend confirm the pressure much more unsteady after March.
I've been told it was likely too high of line pressure. It was peaking in the 230 PSI range in drive early in the year.
230psi in drive?! Good lord...that's so unnecessary its not even funny.
If it was a th400 you would've for sure blown out case lugs if the 1-2 shift was setup too agressive. Kindof surprised you didn't have issues with your 80 in the same areas.
185psi will handle 750hp all day long without so much as a sneeze. Sounds like you did a boost valve/spring then also played with the tune a little too much...or used too much spring, etc. Something wasn't quite right
It was the spring that came in the CK Performance kit, the 230 was peak at full throttle. I'm a novice at this so I didn't know 230 was too much. All my life I seem to learn things the hard way lol. I have since replaced it with the Sonnax booster kit albeit a little late.
Car now has a Jakes D3 brake which calls for unplugging the EPC solenoid. That was done just a couple weeks ago and it broke on my first trip to the track with the brake
I know this is an old thread now. But literally the same thing just happened to me. I ran a pass at the track and let of at 141mph when I started heading back to get my slip realized I lost all gears. I found my pump gear cracked as well. No filter blow out. It did spit oil out the vent as well. Had the car running for 2 years.
did you ever find out what happened? Converter clearance was ok when installed 2 years ago. Could it have been cavitation from slowing down and shifting the oil forward? Or maybe the filter couldn't flow enough. I am running a D1 transbrake.
Thanks for the reply. So your suggesting grinding the inner part of the pump gear that cracked. Were it first has contact with the converter. I assume so the pump gear can slide more easy on the converter single spline.
So I would think then what happened was that the converter and pump gear were to tight and some how cause a premature wear since the converter could push the gear into the pump halves?
Thanks for the pic. Really cleared it up for me. Makes sense if the gear would make contact there bye-bye gear. Ok ill try grinding it down some to make a ramp.
Now I gotta find a pump with a machined cover for my reid bell housing.
4L80E pump failure 
