Signs of a knackered diff or something else?
I brought a CLK55 last year, paid £4k, car was in good condition but it had some issues this why it was cheap.
Long story short if you are in park and put the car in drive or reverse you get a noticeable clunk from the rear. This same clunk also occurs on harsh shifts or heavy acceleration or deceleration.
Was told it was probably a worn driveshaft donut. Anyhow, got under the car and filmed what happens. When engaging a gear there is a lot of driveshaft rotation for reverse but not drive. Drive is a few mm of rotation whilst reverse is quarter of a rotation followed by a thud from inside the diff.
No obvious signs of an oil leak, when you drive normally all seems ok, but harsh driving it feels as if there is play and lag on acceleration as it feels jerky.
Video of diff here under car engaging drive and reverse
https://youtu.be/KhylmCMUjIs
Presume diff is worn?
What are my options
Was the parking brake set when you shot the video? Did the rear wheels definitely not turn at all? If so, then you've got major problems inside the diff.


