37s on the 2014+ Power Wagon's factory 4.10 gears make a soft, slow, fuel-hungry truck. 4.56s restore the factory 33"-tire feel — throttle response, low-range crawl ratio, transmission shift points. On the 6.4 HEMI, 4.30s are acceptable and 4.56s are better. Older 2005-2013 trucks left the factory with the 5.7 HEMI behind 4.56 gears already, so their regear conversation starts at 4.88.
The 2014-and-later Power Wagon comes from the factory with 4.10:1 gears in the front AAM 9.25" axle and rear AAM 11.5" axle, behind the 6.4L HEMI. (The 2005-2013 truck paired the 5.7L HEMI with 4.56 gears and an AAM 10.5" rear — this guide's ratios apply to the 4.10 trucks.) With factory 33" tires, that gives a comfortable crawl ratio and acceptable highway RPM. Bump tires up to 37" and:
Re-gearing to 4.56:1 restores the 33"-tire feel with 37s. The math: 4.56 / 4.10 = 1.112x, which exactly offsets the 37/33 = 1.121x tire growth. Within 1% — you can't tell the difference from factory.
For the 6.4 HEMI (2014+, factory 4.10): 4.30 is acceptable, 4.56 is better. The 6.4's torque masks some of the lost gearing, but for sustained high-altitude crawling or towing, 4.56 is the right call.
For the 5.7 HEMI (2005-2013, factory 4.56): you already have 4.56s. Going to 37s on that truck means 4.88s to restore the factory feel, and the older AAM 10.5" rear limits ratio availability more than the 11.5" does — confirm the ring and pinion is offered for your axle before planning the job.
Cost breakdown:
DIY considerations: Setting up a ring and pinion correctly requires:
If you've never set up a ring and pinion before, the AAM 11.5" rear is NOT a good first-time job. Pay a shop. The $1,200 labor saves a $740 ring & pinion that you'd otherwise scrap from a bad install.
Even if you pay for it, knowing the sequence tells you whether the shop is doing it right and where your money goes.
If you have set up a ring & pinion before, the 11.5 rear is doable; if you have not, this is the wrong axle to learn on — see the parts list and the pw-tires-mt tire decision that drives the whole choice.
The single most expensive mistake is mismatched ratios front to rear — it feels fine in 2WD and then binds and grinds the moment you engage 4WD on dry pavement, and by then the damage is done. Verify both axles got the same gear before the truck leaves the shop. The second is a rushed pattern: a contact pattern that is close but not centered will whine at cruise and wear early, so do not accept "good enough" on the marking-compound check. For a DIY attempt, the realistic failure is scrapping a $740 gear set on a bad first install — which is exactly why the $1,200 labor is cheap insurance for most owners.
| Part | Vendor | Est. price |
|---|---|---|
| Yukon 4.56 Ring & Pinion Set — AAM 11.5" Rear (PW) | Yukon | ~$380 |
| Yukon 4.56 Ring & Pinion Set — AAM 9.25" Front (PW) | Yukon | ~$360 |
| Yukon Master Install Kit — Front + Rear (bearings, races, shims, seals) | Yukon | ~$580 |
| Professional install (shop labor for both diffs) | local gear shop | ~$1200 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.
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