2nd Gen Non-Engine/Transmission Speedo Adjustment

[TStinson]

Anyone willing to share the secret procedure to get the speedo re-calibrated when going to other-than-stock diameter tires? Can this be done with something less than a $$$ OBD-II tool?

 

[dan_gilson]

Typically, the pickup for the speedo is from the ABS tone ring on the diff.

The problem is that it all electronic AND it also feeds the equations for the ABS (if you have).

The timing is set up for the 2 different rear end ratios and that is it.



So, with this in mind what is the fix? The only thing that I know of is to use some varient of a black box that changes the timing of the pulses.



Rickson sells one, It is not cheap (~$240) but is works great. It has 2 positions so that you can have both the winter and summer wheels accurate. You can use it to compensate for the tires wearing. I have been able to get it accurate enough to be dead on for 10 miles on the interstate.



It takes about an hour to install. You have to cut and splice an ABS wire. The instructions are pretty reasonable.



Here is why I purchased this unit. I could live with the speedo being off. It is a pain. I could not live with the ABS not being 100%. Especially with the wife and kids riding with me.



This unit will allow you to run with just about any wheel and tire combo under you and you can still get accurate speedo and good ABS.



I hope this helps.

 

[jabird]

Are you sure Dan?? I dont have the sensor hooked up right now to my ABS ring on the diff. and my speedo works.

 

[JGK]

Don't be afraid to talk to your dealer. I know - scary thought. One of the local dealers here reset my system for my larger tires in about 20 minutes. Charged me something like $30 or $35. All he needed was the number of revolutions per mile for the tire your using. He can look that up or you can.



-Jay

 

[ben_ak]

The Superlift Truspeed is also a option. I have one in my truck and it works well. Very simple to install and they have a decent track record - I only know of one failing, and it was replaced for free. I also like the switch that lets you toggle between tire sizes - useful for me because I use two different size tires for summer and winter.



-Ben

 

[mcdaniel1]

Truspeed... . had mine going on 3 years, it has been rock solid... .

 

[dan_gilson]

jabird -

1) I could just be wrong. (It has happed B4 and will again).

2) The connection for the tone ring for the rear diff is not really obvious.

3) if you do not at least of Rear wheel ABS you may have a different hook up.

4) There might be a pick on the back of the trans. For ABS it is definitely an electrical lead. Not a spinning cable.



I think truespeed is also what I have. The truck has been in the shop for the last 2 weeks so I can't open the driver's door and tell you.

 

[CumminsPower98]

I also use the TruSpeed and it has been perfect for several years now.