I bought my 2014 Chevrolet Sonic used with 38,014 miles from a Chevrolet Dealership. The vehicle was previously a Lease vehicle. This car has been back to the Dealership 3 other occasions in a weeks time for other issues fixed under warranty (new water pump, New PCV Valve, New Front Crank Seal). As long as I've owned the car when the transmission and engine gets hot (usually after a 20 mile commute on the interstate), when I am sitting at a stop light the car will start "bucking", or trying to lurch forward quickly. I always thought that maybe the brakes were not depressed enough as I was still getting used to the car.
A friend of mine that is an Audi Mechanic suggested I change the Transmission Fluid, since the mileage of the vehicle came from city driving, and the recommended fluid change is 45,000 miles. As the son of a Mechanic and having changed the fluid in dozens of Transmissions in my life I went ahead. It was very easy, even easier than changing the oil. As the fluid drained I checked the quality of it only to find the fluid was black and burnt. Looking closely you could see small metallic particles in it. I added new fluid to specs and called the Dealership again. Contacting my father whom is a retired GM Employee (and Mechanic) he found a technical bulletin about the transmission. The bulletin stated that bad Clutch Plates on certain Transmissions can cause a "bucking" at idle. The way to test is to put the transmission in Manual Mode when it is bucking and if the bucking stops then you have a bad clutch plate. Sure enough the next time my car started "bucking" I put it in Manual and it stopped right away. I realized my problem wasn't the brakes, but the Transmission.
I informed the Dealership of the problem and the Service Manager said "Burnt Fluid...well there is nothing we can do about that." I reasoned with him that a transmission with only 38,000 miles should not have burnt fluid. He agreed but said they could do nothing until the transmission started to have serious problems. I explained to him about the "bucking" and the Service Bulletin. They took the car and checked the transmission. The dealership stated "Because we cannot duplicate the problem, we cannot do anything. But don't worry, you still have 2 years left on the warranty.".
Considering my wife and I bought this car to hopefully last us 5 years, that isn't comforting. When I showed the transmission fluid to the Service Tech when he came to get my car he said, "Why are you handing me used motor oil?" When I told him it was the transmission fluid he coughed. According to the Service Department Burnt Fluid is not enough to do anything with, which is contrary to what any other mechanic will tell you. The problem is obviously the change of fluid has improved the performance of the transmission and the "bucking" is less frequent so hard to "prove" to the Dealership.
With the problems this car has faced in a short time, along with other issues myself or my family has had with Chevrolet Vehicles over the years, even with a Father with the GM Employee Discount, I will never buy another General Motors Vehicle again. Especially not a Chevrolet.
I bought my 2014 Chevrolet Sonic used with 38,014 miles from a Chevrolet Dealership. The vehicle was previously a Lease vehicle. This car has been back to the Dealership 3 other occasions in a weeks time for other issues fixed under warranty (new water pump, New PCV Valve, New Front Crank Seal). As long as I've owned the car when the transmission and engine gets hot (usually after a 20 mile commute on the interstate), when I am sitting at a stop light the car will start "bucking", or trying to lurch forward quickly. I always thought that maybe the brakes were not depressed enough as I was still getting used to the car.
A friend of mine that is an Audi Mechanic suggested I change the Transmission Fluid, since the mileage of the vehicle came from city driving, and the recommended fluid change is 45,000 miles. As the son of a Mechanic and having changed the fluid in dozens of Transmissions in my life I went ahead. It was very easy, even easier than changing the oil. As the fluid drained I checked the quality of it only to find the fluid was black and burnt. Looking closely you could see small metallic particles in it. I added new fluid to specs and called the Dealership again. Contacting my father whom is a retired GM Employee (and Mechanic) he found a technical bulletin about the transmission. The bulletin stated that bad Clutch Plates on certain Transmissions can cause a "bucking" at idle. The way to test is to put the transmission in Manual Mode when it is bucking and if the bucking stops then you have a bad clutch plate. Sure enough the next time my car started "bucking" I put it in Manual and it stopped right away. I realized my problem wasn't the brakes, but the Transmission.
I informed the Dealership of the problem and the Service Manager said "Burnt Fluid...well there is nothing we can do about that." I reasoned with him that a transmission with only 38,000 miles should not have burnt fluid. He agreed but said they could do nothing until the transmission started to have serious problems. I explained to him about the "bucking" and the Service Bulletin. They took the car and checked the transmission. The dealership stated "Because we cannot duplicate the problem, we cannot do anything. But don't worry, you still have 2 years left on the warranty.".
Considering my wife and I bought this car to hopefully last us 5 years, that isn't comforting. When I showed the transmission fluid to the Service Tech when he came to get my car he said, "Why are you handing me used motor oil?" When I told him it was the transmission fluid he coughed. According to the Service Department Burnt Fluid is not enough to do anything with, which is contrary to what any other mechanic will tell you. The problem is obviously the change of fluid has improved the performance of the transmission and the "bucking" is less frequent so hard to "prove" to the Dealership.
With the problems this car has faced in a short time, along with other issues myself or my family has had with Chevrolet Vehicles over the years, even with a Father with the GM Employee Discount, I will never buy another General Motors Vehicle again. Especially not a Chevrolet.
- Jeff J., Des Moines, IA, US