Q: Speedometer doesn't register correctly

asked by on October 16, 2016

When I go say 60 on the speedometer in my cherry 2004 Police Interceptor, my GPS says I'm going 70. (30 is 35, 40 is 46, 50 is 57 and so on). I discovered that someone, before I bought it at auction, had to have changed the complete rear end assembly. The Oasis report said my PI came off the assy. line with 3.27 gears but a tag on the rear end cover says 2.73. Also there are tell-all markings on the axle housings in "junk yard" white chalk. Makes sense it was changed for some reason. Can I just change a gear in my VSS sensor or must I need a completely different sensor to match my rear end ratio to my speedometer reading? Thanks so much.

My car has 60000 miles.
My car has an automatic transmission.

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