Jim27569

So I got a MQB 10L80 with the LM2 3.0 duramax. Bought truck new 2021 Sierra. I’ve had these “random” hard shifts at trans warm up temperatures. But no light. So thought it just needed a relearn. But now I have a P0700 and P2812 and cannot put transmission in tow haul mode. I put on a thermal bypass valve on the truck about 30k miles ago. If I get it looked at will they “void” my warranty because of it? Truck is at 68k now. Anyone know?