Hi Guys, I have been a browser of this forum for a fair while now and it has taught many a thing about my car, but despite searching I havent been able to find a solution to my problem.

I own a euro 1991 w124 250D (5 speed manual, N/A) on which the speedo reads over the actual speed by almost exactly 20%. So if I'm doing 60MPH it will read 72 on the speedo. I've had the car for 4 months and have verified this is the case. Now, I can put up with this quite well as I've learned to compensate but ideally it would be nice to sort this out. I still cant get over seeing my speedo at 100MPH when im driving down the motorway, its a bit disconcerting.

Unfortuanetly I have no idea what rear end ratio this car is supposed to have, and havent been able to locate the ratio stamped on the diff housing, but the diff looks original and I would rather not change it unless I really have to. Am I right in saying that the instrument cluster speedos are all of the same on these cars, and the diff ratio compensation is in the gear in the transmission? If so how easy would it be to change the gear?

Thanks in advance

Tom

yes, you must find the part # off your diff and figure out what ratio you have. if correct one, replace your speedo cable first. thats a DIY easy, cheap job. if that doesnt work, go get your speedo recalibrated