2021 GMC Yukon power train problems

“VEHICLE: 2021 GMC Yukon, 5.3L V8 (L84). VIN: [XXX]. Mileage at failure: approximately 88,000. Component: Engine. INCIDENT DATE: XXX While I was driving on a highway, the engine began to misfire and I heard a ticking noise. The check engine light then began flashing, indicating a severe misfire. I pulled off the highway immediately to a rest area. The vehicle was towed to a GMC dealer. The dealer's diagnosis suspected failed valve lifters, and the repair orders call for a misfire diagnosis with the Bank 1 cylinder head removed, and replacement of the camshaft, lifters, and related parts. This failure caused sudden loss of engine performance at highway speed. The engine began smoking. My family and I were in the vehicle, and we were fortunate there was a safe place to stop. I believe this is a known defect. GM Service Bulletin PIP5776, "Misfire Due to Collapsed Lifter," covers 2021 GMC Yukons with the 5.3L L84 engine. It describes a misfire with a bent pushrod leading to a collapsed lifter or a lifter that comes apart, and it attributes the cause to an internal lifter concern. Many other owners of GM V8 trucks and SUVs have reported the same failure, and a class…”

“I believe it’s a transmission. While driving down the interstate and the car just won’t get up and go like it should, and I’m gonna get rear ended. I’ve I’ve taken it to the dealership three or four times. I keep telling me nothing’s wrong.”

“Bought 2021 GMC Yukon Denali new. Transmission failed at 70,000 miles. Engine has now failed at 111,000 miles. Both diagnosed at Capital GMC Atlanta, GA. Cost to replace transmission $8k (GMC paid half). Cost to replace engine $12k (GMC offered no assistance). Engine failure not related to current engine recall/investigation on GMC 6.2L V8 engines. This failure was on the top vs on the bottom (current recall).”

“I was driving normally, going up a hill and the car skipped and lurched forward. Then when i touched the gas pedal the car would not accelerate but the rpms would increase. When I was able to pull over, the car would not reverse, the engine would rev when i pushed the gas pedal but it would not move. I drove it directly to a mechanic down the road and he believes the transmission is shot and agrees that it is part of the problems that GMC is having with its transmissions, and it seems as though my car should also be included. This was an extremely dangerous and frightening thing to happen to a car with no warning whatsoever. I was lucky not to have been in an accident.”

“The contact owns a 2021 GMC Yukon. The contact stated that while driving at various speeds on several occasions, the vehicle jerked and the transmission shifted hard into 1st and 2nd gears. The message "Service Safety Restraint" was displayed. The vehicle was taken to an independent mechanic, where it was diagnosed with a failed valve body. The contact was informed that the valve body or the transmission needed to be replaced. The manufacturer was notified of the failure. The failure mileage was approximately 88,000.”

“Had a valve body failure in mid XXX. The vehicle would not go into reverse and drove it in limp mode to a dealership about 5 miles away. Fortunately they were able to get a new valve body and repair it in one day. Cost was approximately $3,500 and not covered by warranty. The vehicle had about 110,000 miles on it at the time. This is a known defect on this vehicle and a recall should be initiated. Had we started our trip from [XXX] back to [XXX] before the failure occurred, we likely would have been stranded on the highway, or worse.”