Unless something has changed there is nothing that has to be done with gear swap concerning speedo etc. Won't throw codes or any of that. Tire size it does but not gear swap. Speedo and such reads off tone ring on the differential.

 

I can't give you an exact number as far as fuel mileage, but it will difenayely improve over stock. If I were you I would go with at least 4.10. Depending on what you do 4.56 is still great butbetter for towing, when I'm empty a barely ever downshift on hills at all, has to be a pretty big hill. Even towing is awesome, compared to 3.55. If your always driving highway then 4.10 wih your setup.

 

Yeah mostly just drive to work and back each day (4miles city ,5 miles freeway) my engine barely even gets up to temp so i get ****ty mileage regardless but the only towing i really do is 2 or 4 snowmobiles in the winter and i was stuck between a 3.73 (which would still be slightly undergeared for 35's) a 3.92 or a 4.10. Thanks for the advice!

 

I talked to a Dodge technician earlier today and he said there's a place in the PCM entry which must be updated when changing the axle ratio. This is important as it will affect some engine set points and the ABS computer. They've done a couple at his dealership. He doesn't believe you'd get a problem code if you didn't update the computer.

NOTE: If you have a 2012 you may have a ZF axle.

There's a ring and pinion kit for the Chrysler-built axle (05015371AE) that includes a new pinion seal (68056356AA), a front pinion bearing (05072498AA), and a rear pinion bearing (05017438AA).

Best regards,
Dusty

 

Fair amount of gears changed posted on this and other sites. Never a mention of updating anything with gear change. Bet on the assembly line all settings are the same no matter the gearing. Only thing that is different is tire size. There is a place to update that. Now in 2011 or 2012 that might have changed but previous there is nothing to reprogram as the tone ring in the differential housing is giving the info to the computer system. But I bet someone posting that has changed gearing will let us know.

 

Yeah, I have to agree it doesn't seem that the PCM actually needs to know the axle ratio. The speed sensor sends the signal off the tone ring for ground speed. As far as that goes I don't understand why he said it was needed for ABS, for that matter. Maybe it's needed for traction control? I don't think the transmission cares, either. He did say certain "engine set points," which may be valid, and he also said it wouldn't generate any problem codes.

Best regards,
Dusty

 

No nothing required for a gear change. Tires YES. Not to be a s/a but if there is more that must be a 2012 deal as no one has ever posted different. I'm not from Missouri but show in print what is adjusted or why.