8l90 help maybe tuning issue?

[Duramax06703]

2016 gmc sierra 6.2 8l90 trans
tsp cam, whipple 2.9, 3200 stall(circle d) and many other mods. Weaponxmotorsports tune done at local tuners dyno
Right after my last dyno tuning session where we were tuning for the cam and new converter is when this all started. Dyno pulls went great made awesome power, with no slip at all in beetween shifts. Tq managment remained the same with about 20% taken out. Get down the road about 5 miles and it acted like the converter **** the bed. Wouldnt move in any gear. Check the trans temp and she was at 170. Just neutral for every gear. Turn it off let it sit for 10 minutes or so and shes good, got about another 5 miles and it feels like it goes right into neutral. Temp staying right around 170-180. This being a brand new converter I was pretty pissed, tuner said when they drained the fluid it was pretty black and would bet the trans is just finally dying from bad fluid being in there for so long, k bit the bullet swapped in a brand new trans and converter, all is good for the day and today it just did the same exact thing with the wife in the truck(she hates going fast so I didn't floor it once) I've gotten it down to about 45 minutes to pull this trans so I swapped in the stock converter for ***** and giggles and it does the same exact thing. Fluid in this new trans looks perfect as it has 25 miles on it. No metal in the filter, nothing on the magnets.Any ideas what is causing this? This thing ran for 70k miles with the whipple only at much higher boost level and never skipped a beat. I'm pretty competent with hptuners, is there something in the TCM tune that would cause the trans to burn up within 25 miles of easy driving? Whenever it did it on this new trans i was in neutral getting pulled through a car wash and went to leave and it wouldnt move. Any guesses or information would be helpful. I'm away from my laptop as I work out of town.
One thing to point out, I checked the fluid level the 1st go round as per gm specs and it was overfull by about a gallon! I haven't check it this second time maybe I overfilled it again? Is it possible to blow an internal seal bc of too much fluid?

[32vape]

How are you checking the fluid?

[Ben Charles]

Honeslty I wouldn’t have even put a converter In that rig with a whipple..
I’d pull it out and put stock one back in and I bet your problems go away

[Duramax06703]

Per the gm procedure. Warm trans up to temp ive been doing the preferred track session option in the procedure which is 131-149 ?f take plug out of trans check plug if non comes out you add some if oil comes out wait until it dribbles and reinstall plug. This is the only way I've been shown how to do it

[Duramax06703]

I have just ordered a reman 8l90 and will throw in the stock converter, even on that size of cam it really doesn't seem to push through the brakes that bad like everyone says it does.

[Cody_2]

Did you figure it out having same issue

[Duramax06703]

Sorry for the late reply.. Truck is currently at circle d transmission getting a full build. They are supposed to diagnose what happened as they haven't seen it before. I will post an update when I know. Supposed to be done by jan 8th.

[Duramax06703]

Update man circle d went through and they said the wear on the clutches was very odd. Recommended I check tuning. Took it to chuck at HHP. The torque models were scaled completely wrong and the engine wasn't communicating to the trans properly on shift pressures ect. (To my understanding) however chuck through in his magic and now were back to gapping sports cars.

[Duramax06703]

Thanks for the advice on the stock stall. I switched back to an oem converter and it is much more drivable. 3200 was fun for a race car but it was hell trying to drive daily.

[Ben Charles]

You’re welcome