I just bought an 01 2wd daully checked codes this what I got: P0500 Vehicle Speed Sensor 1 Circuit, or No Vehicle Speed Reference Signal 1. no clue what to even look at.

I got one all the time... (Seriously!) Dirt roads get me all the time... http://mopar.mopar1973man.com/cummins/2ndgen24v/abs/abs.htm (Bottom of the page) P0500 Error Code - Explained Since 4 wheel antilock brakes rely on 2 front axle sensors and 1 rear wheel sensor. The CAB is watching the speed output from all 3 sensors at one time. So when on a slick surface like ice, gravel, wet pavement, etc. when you accelerate rapidly and cause the rear tires to spin the rear speed sensor jumps up in speed rapidly and the front 2 sensor could be at zero speed yet. So the CAB can't understand how the rear half of the truck is doing say 35 MPH and the front half is doing 0 MPH. POOF! P0500 code is thrown.

ok sounds like nothing to worry with. Thanks for the help

Ok... Little more insite on this...

If the P0500 is by itself it nothing to worry about most likely wheel spin...

But if the P0500 is with a ABS/BRAKE light I would start looking are ABS wheel sensors...

If the speedometer is working properly then I would replace the front sensors...

If the speedometer is NOT working properly then the rear speed sensor has failed...

I clear mine all the time.I have replaced both sensors it is no big deal.Do you have any plans for the truck? Is it a reg cab?Them are cool they look like a pup.I think a 2wd reg cab dually would make a neat drag truck.