I have a 90 camaro rs TBI! I JUST REPLACED MY STOCK NON POSI REAREND WITH A 3.73 POSI REAREND! MY SPEEDOMOTER IS OFF AND BECAUSE OF THIS MY SPEEDO READ 100 AND TRULY IM DOIN ABOUT 65 THE PROBLEM IS THE ECM THINKS IM GOING 100 SO AT ABOUT 80 MPH THE COMPUTER THINKS IM GOIN 115 SO IT SHUTS DOWN!! WHY IS THIS AND HOW DO I FIX THIS! HYPERTECH DOESNT MAKE A SPEEDOMOTER CALIBRATOR FOR MY VEHICLE! WILL A HYPERTECH OR JET PROM FIX THIS? WHAT IF I REMOVE THS VSS! WHERE IS THE VSS AND HOW DOES IT COME OUT IF I NEED TO REMOVE IT. WHAT ABOUT AN AFTERMARKET SPEEDO?? PLEASE PLEASE PLEASE HELP

 

You need to change the drive and driven speedometer gears in the tailshaft of the transmission. They're attached to the VSS. Go to the Tranny/Drivetrain forum and look there. What kind you need depends on if you have a T5 manual or 700R4 automatic.

Also, please do not type in all capital letters, its rude.

 

I have a 700R4 tranny. Do i need new drive and driven gears?? If i disconnected the speedo cable would it fix it? would a hypertech or jet prom fix this? also sorry about the capitals.

 

No. The only way to fix your speedometer is to change the plastic speedo gears.

If you disconnect it, then the computer gets confused and it will stall out on you when you slow down. You will also get an SES light for a code 24.