Which parts fail
Components named in complaints (automatic and manual transmissions, CVT, axles, driveshaft, 4WD/AWD).
Mileage when the problem started
Owner reports
Selected complaints filed with NHTSA by 2015 Cadillac CTS owners, lightly cleaned up (personal details are redacted by NHTSA).
The contact owns a 2015 Cadillac CTS. The contact stated that while driving, the air bag warning light and the check engine warning light illuminated, and the message "Service Vehicle Soon" was displayed. Additionally, the rear end of the vehicle made an abnormal roaring sound. The vehicle was taken to the dealer, where a multi-point inspection was performed. The dealer replaced the purge valve due to a leak, an oil change was performed, and the check engine warning light was reset. The vehicle was taken back to the dealer to be diagnose regarding the roaring sound coming from the rear of the vehicle. The dealer determined that the rear differential was leaking due to a pinion bearing failure and needed to be replaced. The contact associated the failures with NHTSA Campaign Numbers: 20V038000 (Power Train) and 26V329000 (Air Bags). The failure mileage was approximately 143,145.
The contact owns a 2015 Cadillac CTS. The contact stated while driving at various speeds, there was an abnormal grinding sound coming from the rear end of the vehicle. The contact also became aware of an abnormal sound near the brake pads; however, the contact stated that the sound was not coming from the brake pads. No warning lights were illuminated. The vehicle was diagnosed by an independent mechanic who determined that the differential needed to be replaced. The vehicle was not repaired. The contact related to the failure to NHTSA Campaign Number: 20V038000 (Power Train); however, the VIN was not included in the recall. The manufacturer was not informed of the failure. The failure mileage was approximately 157,000.
The contact owns a 2015 Cadillac CTS. The contact stated that while driving at various speeds, an abnormal rattling sound was coming from the rear end of the vehicle without warning. The contact had taken the vehicle to a dealer where they diagnosed the failure as a leak in the rear differential. The contact was initially informed that the repair would be covered under warranty; however, a few days later, the contact was informed otherwise. He was then informed that the vehicle would not be covered under warranty and was given an estimate for repair. The manufacturer was also notified of the failure and provided a case number. The vehicle had yet to be repaired. The failure mileage was approximately 80,000.
The contact owns a 2015 Cadillac CTS. The contact stated while driving 65 MPH, the vehicle shuddered and made an abnormally loud sound. The contact exited the highway and drove to the nearest mechanic shop at a gas station. The mechanic diagnosed the vehicle and determined that the rear differential was fractured and needed to be replaced. The vehicle was being repaired. The contact related the failure to NHTSA Campaign Number: 20V038000 (Power Train); however, the VIN was not included in the recall. The dealer and the manufacturer were not notified of the failure. The failure mileage was approximately 98,000.
The contact owns a 2015 Cadillac CTS. The contact stated that there was an abnormal loud clunking sound coming from the rear end of the vehicle while the vehicle was shifting into gears. The vehicle was taken to AMCO Transmissions & Total Car Care, where it was diagnosed that the rear differential had failed and needed to be replaced. The contact stated that the vehicle was previously serviced under the NHTSA Campaign Number: 20V038000(Power Train); however, the failure persisted. The vehicle was not repaired. The local dealer and the manufacturer were notified of the failure. The failure mileage was 125,000.
My rear differential gear is failing on my 2015 Cadillac CTS luxury 2.0T. I just reached approx 69,000 miles upon returning from an approx 2,200 mile trip to the east coast from Texas. I noticed a whine like noise after my drive back to Texas that seemed to get louder and louder coming from the rear of the vehicle. I took my vehicle to Firestone for inspection and it was confirmed the rear differential was failing. i was also advised the the seal were leaking as noted in the attached report. I was shown the drain plug which had an abundance of metal shavings present to confirm. The fluid was replaced and I was advised to follow up ASAP. Upon researching the issue I discovered this is a common issue confirmed on the Cadillac forums. …
Was simply driving my normally and out of no where there was a loud pop and driving the car all I heard was a loud grinding noise as I stepped on the gas, and the car would not shift into reverse. No lights or warnings had ever popped up into the dash. Also very strong burning and metal smell came from the car. I have taken the car to an independent repair shop and was determined the rear differential has gone bad. Apparently many other people with similar year vehicles have had the same issues with this make and model of car, to add on another car like mines came into the same shop with the same problem.
The vacuum pump failed and caused catastrophic engine failure. The vacuum pump was constructed with substandard design and the composition of the parts within the vacuum pumps internal components. The vacuum pump is an integral part of the emissions system, the braking system and the engine. This is not an isolated incident as the replacement vacuum pump, even if replaced, will fail again. The pump should have been designed with a shear pin so the engine camshaft would not have been destroyed.
The recall that was done on the 2014-2015 CTS-V should have been a recall on ALL models of CTS because all of the models in the timeframe received the dsame flawed rear differential. My 2015 CTS Luxury has only 80k miles on it and the differential has chunks of metal in its oil. It is the exactaame differential as is in the CTS-V. At any time my rear end will lock up once the dofferential fully eats itself. It is an extreme saftey hazard for anyone driving any type of CTS from 2014-2015.
The rear differential started making a loud whining noise around 53,000 miles. It then turned into a grinding noise. I had it checked by a mechanic and he confirmed it was rear differential that needed replacing. He recommended not driving the vehicle since the differential could completely fail and cause an accident. Not having any mechanical experience, the noise was the only indication of a problem. No warning lights or sensor faults.
Transmission complaints in other CTS years
Frequently asked questions
How common are transmission problems on the 2015 Cadillac CTS?
NHTSA has 20 complaints about the transmission & drivetrain of the 2015 Cadillac CTS, 41% of the model year's 49 complaints. The component named most often is driveline › differential unit (4 mentions).
Is there a recall for 2015 Cadillac CTS transmission problems?
No. NHTSA lists no transmission & drivetrain recall for the 2015 Cadillac CTS, though it has 3 recalls for other components. If the problem is widespread, a repair may still be covered by an extended warranty or a manufacturer service bulletin — ask a dealer.
At what mileage do 2015 Cadillac CTS transmission problems start?
Half of the complaints with a recorded mileage happened before about 80,000 miles, and 10% before 25,000 miles.
Source: U.S. National Highway Traffic Safety Administration (NHTSA) — owner complaints through October 20, 2026, recalls and defect investigations; fuel economy from the EPA. Complaints are unverified reports and are not proof of a defect. How we rate model years.