VonDeutchMB

Ok the car 81 500SEL (Grey market) 105k KMS

The problem

Strange vibration in 3rd and 4th at 2500RPM under load.
Cold transmission it flares into 4th no reverse problems and above 2500 fine (other than tire vibration replacing them soon lots of dry rot)
Recent maintinance changed fuel pump (it was off of a VW but works for now will get a new one soon)
Adusted the vacume pod (seemed to help the flareing some)


I am thinking that I need to do a tune up to fully assess the problem.
Might swap out the B2 and K1 piston and do a full tranny service too.

Would the flex disks do this as well?

Any Ideas??