Best gears for regearing

[Gshane]

Hey I'm getting ready to regear my 2022 Sport. I have some 37inc Katanis about to go on and want to go from 3.73 to 4.88. I'm in the learning process so wanted to know from those of you who've done it. Do you think Dana Spicer is the best route? Yukon? Revolution? Appreciate any advice any of you have. Thx!

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[kevman65]

DANA is what's in there now and a good company.

Yukon has a good reputation, but also has a reputation for being noisy.

I know nothing of Revolution.

 

[Gshane]

DANA is what's in there now and a good company.

Yukon has a good reputation, but also has a reputation for being noisy.

I know nothing of Revolution.

Thx!

 

[bleda2002]

Dana is far and away the best for the advantek axles. Yukon has a bit of a bad reputation in the advantek axles, revolution and nitro are decent but if you can get Dana go Dana.

Also may I recommend 5.13s for 37s, there is only a small difference at highway speed compared to 4.88 thanks to the 2 overdrives on the 8 speed but a better first gear and if you want to go with heavier rims or tires or 38s or even 39s you'll be glad you went 5.13s.

 

[1550jrit]

I run 37” Ridge Grapplers and have 5.38 Dana Spicer gears. I had originally set out for 5.13’s but the back order lead me down a path where I took a chance on the 5.38’s, and I’m super happy I did.

I read through just about every re-gear thread on this forum. On more than one occasion, you’d read comments from those who had re-geared with anything less than 5.13, wishing they had gone deeper. I never once read anyone wishing they hadn’t gone so deep with their re-gear. It’s an expensive endeavor and you really need to get it right the first time. 37’s and 5.13’s (or 5.38’s) for the win.

 

[Vtur]

Dana Spicer gears for Dana's axles.

 

[Gshane]

Dana is far and away the best for the advantek axles. Yukon has a bit of a bad reputation in the advantek axles, revolution and nitro are decent but if you can get Dana go Dana.

Also may I recommend 5.13s for 37s, there is only a small difference at highway speed compared to 4.88 thanks to the 2 overdrives on the 8 speed but a better first gear and if you want to go with heavier rims or tires or 38s or even 39s you'll be glad you went 5.13s.

Thank you a ton for the advice! I just read about Yukons and was leaning towards Dana. You pushed me over the edge. I’ll look at the 5.13s as well. Just gotta find the right shop. The 2 Jeep dealers in my area don’t have much experience with regearing so I might have to drive a couple hours for a good off-road shop. Thx again!

 

[Gshane]

I run 37” Ridge Grapplers and have 5.38 Dana Spicer gears. I had originally set out for 5.13’s but the back order lead me down a path where I took a chance on the 5.38’s, and I’m super happy I did.

I read through just about every re-gear thread on this forum. On more than one occasion, you’d read comments from those who had re-geared with anything less than 5.13, wishing they had gone deeper. I never once read anyone wishing they hadn’t gone so deep with their re-gear. It’s an expensive endeavor and you really need to get it right the first time. 37’s and 5.13’s (or 5.38’s) for the win.

Thx! Yeah - my head's starting to hurt from reading all the different options and opinions, but I agree. I wanna do it right. So thx for taking the time to share your experience. I appreciate it. Did you have a Jeep dealership do it or did you find an off road shop? The 2 Jeep dealers in my area don't seem to have a lot of experience, but the closest quality off road shops are a couple hours away. Thx again

 

[Wheelin98TJ]

Can’t go wrong with Dana.

Or ask the installer and they will probably tell you Dana.

 

[Dougstdig]

Dana Spicer has been in business and provided parts and complete units to manufacturers for how many decades? I'm not opposed to using newer manufactures, but on this expensive of an upgrade without question D/S would be my first choice.

If I'm broken down 1500 miles from home, I'll take what I can get as quickly as I can get it.

 

[Badunit]

From a strictly math point of view with some opinion thrown in that you can ignore:

You can play around with one of the online gearing/tire calculators or use the formula below where you can also change the desired RPM (at a given speed).

Pick a speed and note the RPM in high gear with your current tires and gears. Say it runs 1900RPM @ 70 mph and you would like that to be 2200rpm so it will be a little more into the torque and hp and won't downshift so much. Note that this will be about 2500 rpm@80mph. And say you're going from LT245/75R17 (31.5" diameter) tires to 37's.

New Gear = (2200/1900)*(37/31.5)*3.73 = 5.07 which is close to 5.13.

5.38 would bump your RPMs up about another 100-120 RPM at these highway speeds. That may be more than you want or need at those speeds (I have no opinion here, I don't have 37's) but I bet it would make it a lot more enjoyable at lower speeds. I don't know which would be better for highway fuel mileage, if that is of concern.

Hopefully someone with 37's will verify the RPMs I stated here (roughly 2200rpm@70mph as the baseline with 5.13 gears).

 

[Dougstdig]

From a strictly math point of view with some opinion thrown in that you can ignore:

You can play around with one of the online gearing/tire calculators or use the formula below where you can also change the desired RPM (at a given speed).

Pick a speed and note the RPM in high gear with your current tires and gears. Say it runs 1900RPM @ 70 mph and you would like that to be 2200rpm so it will be a little more into the torque and hp and won't downshift so much. Note that this will be about 2500 rpm@80mph. And say you're going from LT245/75R17 (31.5" diameter) tires to 37's.

New Gear = (2200/1900)*(37/3.1.5)*3.73 = 5.07 which is close to 5.13.

5.38 would bump your RPMs up about another 100-120 RPM at these highway speeds. That may be more than you want or need at those speeds (I have no opinion here, I don't have 37's) but I bet it would make it a lot more enjoyable at lower speeds. I don't know which would be better for highway fuel mileage, if that is of concern.

Within the last day or two, I saw a video that brought up an excellent point. When going into the 5.13 to 5.3x range, you're giving up significant pinion strength. A mechanic was indicating he has never had to repair a 4.10-4.88 (I think) gear set and he's repairing 5.xx almost exclusively.

 

[Jteakus]

Would also suggest Dana.

 

[1550jrit]

Thx! Yeah - my head's starting to hurt from reading all the different options and opinions, but I agree. I wanna do it right. So thx for taking the time to share your experience. I appreciate it. Did you have a Jeep dealership do it or did you find an off road shop? The 2 Jeep dealers in my area don't seem to have a lot of experience, but the closest quality off road shops are a couple hours away. Thx again

I am lucky enough to have a trusted shop in my area, TORC motorsports, who specialize in re-gearing Jeeps. Even though your shop might be a few hours away, definitely worth the drive to have it done right. Since the work will likely take a few days, I’d make the drive and just drop it off. Admittedly that’s not the easiest thing to do, but worth it in the long run. I’ve had my 5.38’s for about 8k miles and have had zero problems and tons of fun. My truck on 37’s is snappier than a stock Mojave.

 

[Panthers65]

5.13's and BFG 37s here (Small 37s) and I'm real happy I didn't do 4.88s. My last take of gas mix city and high was 18.3 mpgs and towing my boat is way more comfortable than the old 4.10s.

I went with spicer gears too, a light hub on acceleration, but it's nothing compared to the tires.

And I definitely wouldn't have a dealership do this. Even if they say they will the gears are aftermarket, not a factory/warranty part. Ask your local off-roading groups or local car groups for recommendations on gear installers. Plenty of local shops around that know what they are doing. Not a general maintenance garage but an aftermarket shop.

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