I have not had any transmissions problems so far, but that could be because I am good to my truck and I dont do burnouts all the time and high psi boost launches all the time. The dealer that I deal with has been getting business from my family since the 80's and they treat us really good. The service department knows this because the service department manager grew up with my dad and uncle. I have taken my truck in for service work with a bad HPFP when my DPF was gone and my Spartan tuner was hooked up. They still replaced the HPFP without voiding my warranty. The diesel tech says that as long as my issues are not directly caused by my tuner then he will work on the truck because other STOCK trucks have had the same issues....I think that is fair. I plan on getting a Suncoast when my tranny goes out, so I wont cost FMC a dime