It could be the shock absorbers. I replaced mine with KYB because someone recommended them and they were crap. They wore out after 35,000 miles and were leaking oil and rusted on the piston shaft and were sqeaking to a point where it was embarassing. I purchase BOGE shocks and they are excellent. Look at the shocks the rust on he shaft could be it.

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1990 190E 2.6
1996 Grand Voyager 3.3
1985 Mustang GT 5.0 5 SPD
1982 Suzuki GS 750T