Neck brace after w124 downshift to pass.
The car runs great except when i am on the freeway and have to stomp on the gas....downshift...wait..wait....thunk... now I am in third gear watching the speed increase and gas mileage decrease. Smooth as silk in all other normal driving applications.
I have found through my search on this site talk about rear diff. mounts. could this be the poblem?
Also I read about "vacuum modulator and associated hoses and connectors " Where are these things in the merc. manual? where are these things in my car?
1988 300E 171k (700 miles since the head gasket job I did and it runs great!!!)