Two problems related to automatic transmission have been reported for the 2017 GMC Sierra. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2017 GMC Sierra based on all problems reported for the 2017 Sierra.
The contact owns a 2017 GMC Sierra denali. The contact stated that while driving on the highway at an undisclosed speed, the vehicle jerked, failed to accelerate, and stalled. The vehicle was unable to shift into third gear. The check engine warning light was illuminated. The vehicle was drivable and was taken to the dealer. The vehicle was diagnosed with a wiring harness failure on the transmission. The vehicle was repaired based on the diagnostic test but failed to fix the vehicle. The vehicle was parked at the residence and was undrivable. The failure mileage was approximately 103,000.
The contact owns a 2017 GMC Sierra. The contact stated that on several occasions while accelerated at various speeds, the gears inadvertently shifted from high to low and the rpms increased. No warning lights was illuminated. The vehicle was taken to the dealer where the failure could not be determined however, the failure recurred. The vehicle was then taken back to the dealer where it was diagnosed that the valve body, the clutch, the piston, and transmission plates needed to be replaced. The vehicle was repaired however, the failure recurred. The contact stated that while driving, he felt a hard shift into lower gear and felt the gears had shifted and jumped into third gear without warning. The vehicle was taken back to the dealer, but the failure recurred. The vehicle was not repaired. The manufacturer was not notified of the failure. The failure mileage was approximately 60,000.