I had one of these wear me out as well. It turned out that we replaced the tranny and controller (because you have to replace them both on the 97 to get the updated controller). This fixed the problem.

Also, be sure the tires are evenly worn. IF one or two are a little more worn, IT will cause these speed sensor problems.

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Benzmac:
Donnie Drummonds
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS