Regearing Dana 44 Axles
This page is scheduled to publish 6/1/26.
Don’t be afraid of setting up your own gears. It does take some specialty tools, some patience, (and possibly an absolute fucking WAR to get the unit bearings loose,) but anyone can do it.
Introduction
My Jeep came with 3.73 gears, and if you think those gears would be horrible with 37″ tires, you’d be wrong. It’s not bad. Not great, but also not bad. In fact for daily driving I’m not sure you need to do anything. With the big power of the 392 and the 8 speed auto the drivability is totally fine. At 70 mph it will stay in 8th most of the time. Starting from a stop is totally fine, it rips thru 1st and 2nd pretty quick.
However, one thing I don’t have is a good crawl ratio, at least not as good as I could have.
Let’s look at various scenarios using the specs for a stock 2022 Rubicon 392.
Transmission
Here are the gear ratios of the TorqueFlite 8HP75 transmission.
| 1st | 2nd | 3rd | 4th | 5th | 6th | 7th | 8th |
| 4.71 | 3.13 | 2.10 | 1.67 | 1.28 | 1.00 | 0.834 | 0.67 |
Tires
The standard tire on a 2022 Rubicon 392 is the LT285/70R17C BF Goodrich KO2 All-Terrain which has a diameter of 32.8″ (and weighs 50.3 lbs)
Transfer Case
The low range in the MP3022 Selec-Trac transfer case is 2.72:1
Extreme Recon Edition?
For additional comparison, lets include the Extreme Recon edition. This optional package has the same transmission and transfer case but gets 4.10 gears and 35″ tires.
Engine RPM at 70 MPH
Lets do the math on 70 mph in 8th gear (and 7th). The important value in this table is the RPM column.
| Tire | Trans Gear | T-case | R&P Gear | RPM | Notes |
| 32.8″ | 8th | 1:1 | 3.73 | 1792 | Stock 392 |
| 35″ | 8th | 1:1 | 4.10 | 1846 | Extreme Recon 392 |
| 37″ | 8th | 1:1 | 3.73 | 1588 | -13% Stock -16% ER |
| 37″ | 7th | 1:1 | 3.73 | 1978 | +10% Stock +7% ER |
| 37″ | 8th | 1:1 | 4.10 | 1746 | -3% Stock -6% ER |
| 37″ | 8th | 1:1 | 4.56 | 1942 | +8% Stock +5% ER |
| 38″ | 8th | 1:1 | 4.56 | 1891 | +5% Stock +2% ER |
My current setup is 13% under geared from stock. This explains why it doesn’t stay in 8th on the highway and it will drop into 7th a fair bit. And not that I’m a big fan of the active variable displacement but it almost never drops to 4 cylinder mode at highway speeds. I’m not entirely sure if it’s supposed to, but that system is there if the motor feels it doesn’t need to run all 8 cylinders.
First Gear Crawl Ratio
| Trans Gear | T-case | R&P Gear | Final Ratio | Notes |
| 4.71 | 2.72 | 3.73 | 47.79 | Stock |
| 4.71 | 2.72 | 4.10 | 52.53 | +10% |
| 4.71 | 2.72 | 4.56 | 58.42 | +22% |
Tire Circumference
And the final bit, the difference in tire circumference.
| Tire Size | Circumference | Increase |
| 32.8 | 103″ | Stock |
| 35 | 110″ | +6.8% |
| 37 | 116″ | +12.6% |
Which gear would you choose?
Looking at the chart above, knowing I have 37″ tires, which gear would you choose?
I think I’d be perfectly happy with the 4.10 but given the extra weight of 37″ tires I didn’t want to be “worse” than stock so I picked 4.56. Having driven with 3.73 gears for almost 2 years I know the 4.10 would be really good too, in fact if you ask me on a different day I might say 4.10’s are the way to go.
One of the benefits of the 4.56 gears is the ability to step up to 38’s or even 39’s in the future. However I think 39’s would really be pushing my luck with Dana 44 axles, even with RCV shafts.
