6L90 TCC failure at 50,000 miles. First one failed at 25,000.

[s10dragracer888]

Hello all.

 

I am a semi-frequent user of GMTrucks.com. I’ve had several cosmetic and suspension modifications to my truck (Bilstein 5100’s, roadactive suspension, hellwig rear sway bar, interior mods), nothing major in the drivetrain. I just crossed 50,000 miles, and it looks like yet another TCC failure (first one at 24,500 to 25,000 miles). It’s a 2020 Custom Trail Boss, 4.3. When the first converter failed, they ended up putting 2 thermal bypass valves in it. After the last TBV change, transmission never sees over 150°.

 

What do I need to do to have GM put a better converter in my truck to prevent future hangups (sonnax, maybe)? How should I approach this to ensure I don’t keep losing my truck for weeks at a time?

I don’t overload it, I don’t dog it, and the fluid still looks clean (changed with last thermal bypass valve at 30,000 miles, total fluid exchange and filter replacement). It seems like every 25,000 miles, I’ll be back for another torque converter. I don’t haul or tow frequently. When I do, it’s usually no more than a single axle utility trailer with some light household refuse, or an enclosed single wheel with a flat track motorcycle in it. Bike weighs 600 pounds. Tongue weight below the 1,760 payload rating on the sticker in the door. I’ve never gone more than about 40 miles when towing. Usually interstate or rural rustic road (55 mph and no traffic)

 

Any suggestions? I really like the truck and don’t want to trade it in. It suits me for what I need, and I’ve put a lot of time and love into this machine.