Crystal 2024

My husband is a master mechanic & he can't fix this problem! He has put a new transmission in. He's tried 4 new torque converters. He has flushed and changed the fluid a million times. Tried all the stuff that could go in it & NOTHING WORKS!!! We bought this truck used from a dealership but they were aware of this problem. It can not be fixed & the dealership will not do anything about the problem if it's over 100k. We paid over $25k for this truck with over 200k miles but Chevy trucks usually run for more than 350k miles & still are strong if we'll taken care of. This is a problem & needs to be addressed!!!