Speedo Calibration?

[RichardTaylor]

:-laf

Hey, can the speedo be corrected without installing an aftermarket unit? I heard that the 03 Auto-trans can be recalibrated by the dealer, is that true?

What are my options and how accurate are they? I have an 03-2500 quad cab 4X4 Auto/Trans with 33/1250 tires

 

[JVolpe]

Yes the RPM(Revolutions Per Mile) is a computer setting that can be easily changed by the dealer.



I have seen many posts on various forums about dealers saying that they cannot/wont do this or charging anything from 0 - $100 for doing it.



Get the RPMs for the larger tire from Manufacturer web site or use one of the many Tire Size calculators online.



My dealer did it in about 5 minutes and did not charge me anything.

 

[Matt400]

The dealer can do it with a DRBIII scan tool. They will either plug in the tire size or tire RPM depending which menu the tech chooses. I had mine changed to 636 RPM and its spot on with my GPS.



RPM is a more accurate selection because a 33" Goodyear can a have a different RPM than a 33" BFG as they come from different molds.



What 33" tires did you get? Oo.

 

[RichardTaylor]

Thanks for the info, I have the AVON Mud Terrain Radial SXT 33/1250's I have about 10,000 miles on them so far and I like them.