engineer520

I just bought a 1998 Mustang GT Convertible. Auto Trans. 125000 miles. The precious owner said the car had a chip install from a precious owner. He also said the speedometer reads high. I'm traveling down the road at what the speedometer say's at 80MPH @2900 RPM's. This is on a 65 MPH highway. People are passing me up like I'm standing still. I coming to the realization the rear end gears have be changed. I know the trans is going through all the gears. What is the factory gear ratio for this car? Any help would be greatful. Thanks Jerry

Js88lx

2.73's!

Murgatroy

Do you have a GPS App on your phone, or a GPS?

I haven't used in dash speedos in any of my cars for years. I rely on a GPS reading.

engineer520

Yes I have a GPS app on my phone. I'll give it a try. My main issue is not the speedo, but the high rev's. I'll have to jack it up and check the rear end ratio. 2.73? Holy cow. I'm sure I don't have that in the rear end. Thanks Jerry

engineer520

I jacked up the care yesterday to check the gear ratio. With 1 full turn of the wheel, the driveshaft turned 4+ times. So I'm guessing a 4.11 or so. Something else happened tonight. I was backing into the garage. Put it in park, then the RPM's revved up big time. What is up with the car? Help.