pump gear broke on the track in 4th gear, had the transmission rebuilt then 1st pass on the track it did it again.

 

Pump gear ? hmm ok maybe I have answer, At higher RPM and LINE in lockup (I am assumming you would be locked in 4th at WOT ) all these things are pushing the converter away from the trans, Do you or can you get any pictures of the broken pump gear from each side ?

 

Yeh twice in a row and yes its locked, so what would be the fix then? Hold it in 3rd longer? Ill get pictures from him.

 

Actually check the converter to flex plate clearance and make sure it starts at the lower end about 1/8 inch . And yes get phtos of the broken gears that can tell us alot ,

 

converter was measured when installed, this is strictly a track car and honestly it has alot of top of the line parts. I wont name the transmission company but it was built by a well known company. Tuner says hold it on 3rd over the finish line.

 

Does he lock it in 3rd at wot ?

 

Odd deal. Looking forward to the pictures.

I would think converter spacing or line pressure on a stock 13v rotor would be the culprit here......

 

Converter spacing is too large or the pump gear is catching the crescent in the pump cover and breaking. Most like too much converter spacing.

 

This would be a 4L80 wouldnt it? Not a 60?

 

Hughes 4l80e and the converter spacing was measured. It lost all gears, had to pull it off the track with 4 wheeler. The first time it happened pump gear was replaced and clutch packs and now it did the exact same thing. Transmission is on its way to Georgia to be taken apart and evaluated by his trans builder but knowing what happened the first time he knows it did the same exact thing again.

 

4L80e

 

What was the measurement then?

 

Well sh*t, no wonder why im confused lol I thought we were talking about a 60. Guess thats what I get for not reading all the way

 

Converter spacing was measured to 1/8, if fact the first time it happened it had circle d 258mm converter and when he had the transmission fixed he put circle d 252 converter.

 

Guys its a guaranteed known breakage point, this car can not shift into 4th gear at wot. You can run it all day up to 3rd with no issues but as soon as it hits 4th gear the transmission will be smoked.

 

Looking forward to photos of the pump gear .

 

I havent received them yet, once i do ill post them. Transmisssion is going to Georgia for rebuild and he also has a new long block being built and from what im hearing GPI is supposed to tune the car for him this go around to rule out any tuning concerns.

 

I dont think tuning but and gear picks will verify between HIGH LINE AND TCC LOCKED both push converter forward I have noted this on a former DYNO I use to test on , in those conditions since the trans had no rear support enough presure existed to literally raise up rear of trans a measure cooler line presure goes very high ,
So I am betting either due to a weak flex plate assuming clearance good or even thrust engine thrust bearing excessive . Converter is pushing far enough forward to disengage pump , Photos will tell the tale.
The way I deal with this possible issue is to place a orifice restrictor in converter feed for units I know will operate at high line or constant max line. Also exactly what max line is at high RPM should be check after reasemble and install . It may be just "TO DAMN HIGH" Llie the rent lol. I was helping a guy years ago with a E40D that had been set up as full manual max line with switch for lockup , He didnt have pump issues but had a couple LOCKUP CLUTCH failures. We put a gauge on it and I had him go wot NOT LOCKED 375 PSI and we had our answer the extreme presure was distorting the converter face in lockup and destroying the clutch, worked out getting it down to 250 psi max using one of those I dont care for them but it worked presure limit mod from a transgo kit and no more issues. I would have gone a different route but hey it did work.
Something to check IMO for sure.

 

ill definitely pass on the message to him, i copied and pasted your message and gave it him. Hopefully i get the pictures from him soon.

 

Frank i gave him your number, if someone reaches out by the name of Colby or nickname CoCo thats him.