2018 Mercedes-Benz CLA-Class Powertrain & Transmission Problems

My 2018 Mercedes-Benz CLA250 4MATIC is experiencing a knocking noise from the rear differential at low speeds. The issue poses potential driving hazards, including possible loss of control and increased wear on drivetrain components. The noise may indicate a failing differential, which could suddenly fail while driving. I have contacted the dealer, but no specific recalls or factory service announcements have been identified for this problem. This appears to be a common issue reported by other owners. At the recommendation of the service technician, I replaced the rear solenoid, at the cost of $400, but no improvement. A rebuild of the rear differential was the recommendation.

2018 CLA250 30k miles, leaving the airport the car suddenly felt as if it lost power and slowed un-commanded. It then began to operate normally for the 50+ mph drive home. Upon reaching my neighborhood, the car began to make a clunking, popping sound when under load less than 30 mph. The days after the vehicle continued to experience the same issues every time it was driven. I took the car to a local trusted mechanic and he said it’s the rear differential and most likely failed pre-maturely and it’s not work he can do. He said a rear differential failing with 30k miles would be extremely rare and recommend I reach out to the manufacturer to have it replaced and to keep him updated as to how Mercedes handles this. After taking it to Mercedes of Bellevue the service adviser said this is common on CLAs and GLAs since 2014. Even to the point saying he has a GLA and hasn’t had the issue yet luckily. After speaking to the service manager at Mercedes of Bellevue and asking him directly if he has ever heard of a rear differential failing with less than 30,000 miles on the car he said “no”. After bringing my car in the service advisor said “yes, he has have seen a lot fail to the point i worry about it” as he has the same rear differential in his car. My car is 10 months out of time warranty but 20,000 miles under the mileage warranty. Looking online on the CLA250 owners forum this does seem to be a common issue on CLAs, GLAs and other models that use this rear differential.

Regarding 2018 CLA 45 AMG: On 9-21-21, while I was driving approximately 45 MPH on a 4 lane road, suddenly the car completely shut down. A message simultaneously popped up that the car was disabled and instructed me to look up in manual. Immediately I turned right into the first driveway where the car came to a stop. I was able to restart car and drive home. At that point, the car's total mileage was 17,189. 10-7-21: Deeming the car unsafe to drive, I had the car towed to Mercedes-Benz of Raleigh for a pre-arranged appointment on 10-8-21with service advisor Christopher Moore. After the tech ran numerous tests, he found the ME control unit was faulty and replaced it at no charge. Since I drove it back home, I haven't driven it since.

ACCELERATING OUT OF A LEFT TURN, THE CAR HESITATED MOMENTARILY THEN THE ENGINE COMPLETELY SHUT DOWN IN TRAFFIC. THE DASH INDICATED THAT THE CAR HAD BECOME INOPERATIVE, POSSIBLY DUE TO THE ELECTRONIC STABILITY PROGRAM (ESP) ISSUE.