I have an 06 4.0 and I just put a different rear end in it, it's got 3.73 gears and a posi diff.

Odd thing is that the rear end came off of a 05 4.0, so I don't see why the speedometer would be off. But it is and it's a problem, it constantly tells me that I'm going about 7 mph faster than I actually am. Just wondering if there is anything I could do to fix , or a shop that could fix it.

Thanks for any and all help

 

So no one has a solution?