I just went from 3.73 to 4.30 gears on my 2007 f250 6.0. It has the standard Sterling 10.5 rear and Dana 60 front. My mechanic friend who did the swap said the ABS light came on during his test drive but the truck drove fine. I was of the understanding that the truck would not need to be recalibrated for proper speedometer and transmission function, but what about the ABS? Any thoughts?

 

How was the speedometer? Was it reading correctly? If so you should get the truck scanned to see which codes are showing.

 

Based on what you're telling us, I would guess that the VSS sensor on the rear differential has a minor issue, or was installed incorrectly during the gear swap. Like Tom asked, is your speedometer working OK?

 

Thank for the replies. The truck is still at his shop. He didn't mention anything about the speedometer not working correctly but I'll clarify that with him. I'll check for codes when I pick it up later today. Am I correct that nothing needs to he recalibrated electronically due to the new gears? The gear swap was all we did.

 

No, nothing needs to be recalibrated because of the gear change. The speed sensor operates off of a tone ring in the rear differential. This tone ring spins once for each tire revolution, and it doesn't care how many times the pinion has to spin to make that happen.

 

Still scratching my head on this one. I drove about 100 miles today. The speedometer works fine. The truck drives and shifts fine. I have the PHP/edge tuner/monitor and its not finding any codes.

 

OK, just to be certain - if I change the ring & pinion in my 2012 F450 from 4.30 to 3.73, I don't need to get the speedo/odometer changed because the tone ring on the rear ring gear is responsible for this?? Will I need a new/different tone ring?

My greatest concern is that I am in 6th gear by about 35 mph with the 4.30s. Any speed increase beyond that is all RPM - but boy, does it roll.

 

That is correct , the speedo will stay the same. The only way it would change is if you changed the tire size..