Just bought my truck, it has 170k on it and I bought a extended warranty 2 yr 20k . Now motor is tight but I have heard that this slush box doesn’t like over 400 hp and miles over 170k. I am thinking tranny is about toast, but still works ( no trans codes ). Would like to have it rebuilt under my warranty but it’s still working. What kills the transmissions and won’t look like I did something to make it fail? Would like a computer that I can tune. Bump the hp bout 100 to125 without any other mods but worried stock computer will show mod and void warranty

 

Do a high pressure flush. That usually kills high mileage transmissions that are otherwise working normally.

 

Thank You