L99/6L80E Issues

[jame2ss]

hey guys, having some problems with my transmission as of recent. The car is a 2015 2SS with an L99 and the 6l80E. The trans does not want to shift at anything above light throttle all the way through wide open. However, the only time it appears to be an issue is the 2-3 shift. The car has a set of headers, a cat-back exhaust, a cold air intake, and a street tune from a local performance shop. I brought the car to the tuner first, and he could not find a problem with the tune, and even after resetting the trans to the stock tune, it was still having the same issue. Any, and I mean any, insight will help. I'm pulling my hair out trying to figure out what could be causing this. Just had the trans flushed as well by the dealer at 55k miles.

[Machh5]

Dealer should be able to diagnose its very quickly. Their scan equipment is almost fool proof. That's where I would go.

[Vegas Bound]

Drum and sprag, time for a rebuild.

[jame2ss]

Originally Posted by Machh5

Dealer should be able to diagnose its very quickly. Their scan equipment is almost fool proof. That's where I would go.

I picked the car up from the dealer today after my tuner reccomended a trans flush. You think they would have noticed anything, no?

[jame2ss]

Originally Posted by Vegas Bound

Drum and sprag, time for a rebuild.

Could you elaborate on this a bit more?

[Vegas Bound]

Originally Posted by jame2ss

Could you elaborate on this a bit more?

WOT pulls wear the drum and sprag. First indicator is failure to shift at RPMs above idle/very low. Changing fluid seems to make it seem worse. Older fluid has particles in it that create more friction for the sprag to grab the drum. I would be interested in seeing what the fluid looked like when it was drained. If it had a metallic sparkle, it's time for a rebuild.

[Machh5]

Originally Posted by jame2ss

I picked the car up from the dealer today after my tuner reccomended a trans flush. You think they would have noticed anything, no?

They didn't diagnose it? Are you kidding?

[jame2ss]

Originally Posted by Machh5

They didn't diagnose it? Are you kidding?

They did not specifically tell me what the problem was/is, but on the reciept they gave to me it reads as follows: "The transmission shudder is cause by a TCC regulator sticking in the lower valve body. Control valve lower body and upper body replacement tech remove the lower and upper control valve body and recondition valves and clean debris from the valve body. Tech road test and found normal transmission operation."

The only way they could have found the 2-3 shift normal is to not give it more than 25%-35% throttle. I dont understand it either. Vegas bound is scaring me lmao. It just doesnt make sense to me that I would have an issue with only bolt on power.