I have a 1985 iroc witha 3.73 rear end (which is not the origonal). When I am going about 65mph the speedometer says I am going 100mph. I have tried many different speedo gear combinations but cannot seem to get the right one. If anyone has a 3.75 rear end, and knows the speedo gears that they have please let me know. I am racking up miles like crazy.

 

Well at least you'll never get pulled over for speeding! "Son, do you know you were doing 22 in a 55 mph zone?" "Officer, my speedo said 60!" It could be worse, and be the other way around... and you'll probably get more luck with this question in the transmission & drivetrain message forum!

 

Disconnect the speedo so your miles don't shoot up 'til you get it fixed. I'm not sure which ones you need but your GM dealer should be able to tell you which color you'll need. Also this would have been better on the tech/general engine or tranny board. Do a search on those boards also, many people have switched to 3.73 gears so chances are you'll find what you need in the archives.

-Matt

 

sorry put it in wrong section.