We just installed a refurbished original factory instrument cluster and now that new speedometer is reading 10 MPH slow. When you first start you must get to 20 to read 10 and it continues to read 10 MPH off throughout the speed band. Has anyone seen this before? UPDATE - We validated the gearing is correct today, for a 3.91 with an overall tire size of 26 we needed a 2538940(Orange), which is what we have. We are still having the problem and checked to see if there was any bind in the cable, nothing seems hard when we checked it. Lastly it is coupled to a 4 speed manual.