Hi,
My w124 seems to knock once 'sometimes' each time it downshifts from4 -3-2-1 depending on which gear it is downshifting from. Upshifts are smooth as ever. Even when i down shift from D to 3 or 2 this happens but only sometimes. Does anyone know why this could occur? I'm new to MB's and cars in general but am willing to learn as much as i can.
Thanks for your help.

jm