Speedometer runs slow with stock tires.

[jim817]

Got a question for you guys. I have an 1983 CJ7 that was supposedly stock when I got it. From what I can tell, there are no mods other than some homemade shackles. My question is what would make my speedometer run slow with stock tires on it. Wouldn't it run fast if the PO had change out the speedo gear from running bigger tires?

 

[mylittlecj5]

How slow is it running? I've seem some perfectly good speedos read up to 10% off when calibrated against GPS or radar.

 

[mtnwhlr]

You just need to change out the speedo gear a good Transmission shop can hook you up.

 

[jim817]

I just noticed that it was 5MPh slow at 45MPH on the GPS. I will have to check it at different speeds.

 

[73CJ]

Are you sure you've got stock tires now?

 

[jim817]

235/75/r15's

 

[73CJ]

13 revolutions per more. Shouldn't make a difference.

I had a plastic gear on mind that was slipping when warm. JB Weld fixed that. You pull the tail shaft housing off. 5 bolts and drop the driveshaft.

Did the PO change the gears in the axle?

 

[jim817]

I have no idea if the PO change the gears. I will have to open them up and look.