The only problem I had with them is the used parts they sent me. Supposedly the rear planetary hub doesnt break, but mine did, in three pieces right at the oil holes. I had pat send me a new one with a new output shaft. Not only were all the parts used and dirty, but the part that never breaks was cracked right at the oil hole, and the output shaft was for a 4 wheel drive. He also told me that the tci servos leak and the stock ones are better. I thought that was a big problem with the 5r55s was the intermediate servo? Pat has been more than helpful with any questions, it just seems their quality control is shit.