My car is 10 years old with about 124,000 miles on it. It’s making grinding sounds in the rear end while turning. I got the rear serviced with a LSD additive a few times which made it drive quietly for about 3000 miles. But it went back to the grinding noise again. I also got loud rattling slapping sounds when I start the car just for a couple of seconds. When I turned it off I heard a little knocking sound as the engine comes to a stop. And when I dove down the road I heard a noise similar to a spark knock. I have used premium gas all of the time. I noticed a great deal of power loss, too. I thought that I might have some chain stretch going on. Is that possible? But I don’t know for sure. It has the original water pump. My Check Engine light never came on, so I don’t know if it works or not. Do you have any ideas?
The fluid in the rear end can be inspected for extensive wear on the gears inside and the drive shaft joints for any amount of play. Check all of the vehicles fluids to make sure they are full and clean and change any that look dirty or smell burned. If you would like to have this looked into, a certified professional from YourMechanic can test your car and diagnose the cause of the noise and can help perform any repairs needed.