Certified Transmission correctly diagnosed the problem with our 2002 GMC Envoy, which turned out to be a bad solenoid and not the transmission. The repairs were done quickly, honestly, and at a very fair price. We worked with Jeff during the entire process and he was outstanding, kept us informed, and did not try to sell us anything we did not need. My wife loves her car, so it was good to hear Jeff say he's seen our model reach 300K miles. We give Jeff and Certified Transmission 5 stars across the board, and we will be a returning customer. Thank you Jeff and C.T. for an excellent customer experience, the best we have had in this area!