KithicHunter

So I just got my truck back from the shop yesterday after they finished putting 4.56's in it (cost me a pretty penny, too...) and the speedometer is way off which is to be expected. It's off by quite a bit, a little under 30mph difference (70 mph = 90 on the gauge).

I definitely want to get this corrected ASAP but I've heard a few different things about getting it done. My first thought was to use my EDGE Evolution Tuner which has an option to set the axle ratio, I used it to go from STOCK to 4.56 but as soon as I started the truck it threw the P2601, or put the truck into "engine failsafe mode". I uninstalled the tune and put it back to stock and the truck ran just fine, no CEL, no failsafe mode.

My second thought was to take it to a dealer and have them flash it, but someone told me most dealers won't change the settings to accommodate 4.56s and 37 inch tires so I'm at a loss.

Has anyone here done a gear swap and dealt with this issue? Or had it fixed?

Any help would be great!

ol_blue

I'm not regeared, but used my Edge to recalibrate for bigger tires. If you wanted a roundabout solution, i guess you could just change the tire size in the programmer until it aligned with your actual speed. I know this wouldn't be the proper way, but probably the cheapest

KithicHunter

I'd have to increase the tire size a lot!! I have it set to my actual tire size now, 37... means I'd have to go 40+ to start seeing some regulation on the speedo, does the Edge even go up that high? I haven't checked.

Z7What

A SCT should fix it. That's what I used on my 03 with 4.56s and 38s. Was dead on!

Wayne

KithicHunter

A new Tuner like the SCT is a bit out of my price range right now, the regear kind of tapped me out for a bit... plus, I don't see why the edge shouldn't be able to do it... the option is there to change the axle ratio, but for some reason the truck flips out when I change that particular setting...

Z7What

Try giving Edge a call!


Wayne

BassAckwards

Actually you would have to go down in tire size because the lower gears are equivalent to running stock gears with smaller tires. What were your stock gears?

If you had 3.73 and if my math is correct you wanna input like a 30" tire. But don't quote me on that.

KithicHunter

I'll try lowering the tire size, couldn't hurt! lol.

I guess I'll try giving EDGE a call, too. But I can't be the only one who has regeared with this problem!

KithicHunter

Thanks everyone for the replies.

Bass, you were right, it was just a matter of lowering the tire size until the speedo regulates, ended up being around a 33 inch tire.

Thanks guys.