gearing and 38

[paparex]

Looking to see if any other 392 owners that like to wheel are running 38 and have upgraded the gearing to 4:88 or 5:38. The factory 4:56 is on the way out

 

[Un4seen4]

while not 38s I am running 37s that are Es so they are heavy bitches, I find the 4.56s not too bad

personally I would prob go with a deeper T case vs gears if you already have 4.56s, it would prob be more cost effective to do first imho.

I had 5.29s on a previous rig and they were practically unusable anywhere but the rocks when I played with the big boys.

I think this may be a good combo setup from what I have experienced wheeling my 392 so far.
35/37s--456s and 2.7 case
37/38s--446s and 3.0 case
38/39/40-4.88/513s and 3.0 case

 

[Warped]

I ran 5.13 gears on my 38s, but it was on a V6. Decided to go no more than 37s on the 392 and keep the stock gears..

 

[paparex]

My stock rear dana 44 blew up so i upgraded to a Spicer Dana 60 w/ 4.56 to match the stock front. Now upgrading the front to a Dana Spicer 60 but 4.56 not available wtf......... So the Delima. I just put on Nitto 38 trail grapplers vs the 37 trail grapplers i had and i have to say its a perfect fit really feels good, not a whole lot of stock stuff left
I have to regear the rear and getting a new front end 4.88 i think is the best all-around option, Atlas transfer case to follow by year end

Thanks for the replies

 

[paparex]

My stock rear dana 44 blew up so i upgraded to a Spicer Dana 60 w/ 4.56 to match the stock front. Now upgrading the front to a Dana Spicer 60 but 4.56 not available wtf......... So the Delima. I just put on Nitto 38 trail grapplers vs the 37 trail grapplers i had and i have to say its a perfect fit really feels good, not a whole lot of stock stuff left
I have to regear the rear and getting a new front end 4.88 i think is the best all-around option, Atlas transfer case to follow by year end

Thanks for the replies

37 Ridge grapplers

 

[averyh45]

38 nittos here and stock 4.56 gears. No problems at highway speeds, fuel efficiency dropped about 1mpg average, no noticeable power differences. I wouldn't worry about it.

 

[jeepguru]

IMO, a 4.88 gear would be where you want to go with 38s. If you have 40" tires anywhere in your future, then 5.13s are the solution. And I never recommend a 5.38 ratio with the OEM Dana 44 axles as the pinion is so small at that ratio, but you mentioned upgrading to Dana 60s, so the pinion size increases and 5.38 becomes acceptable. But, I wouldn't run that ratio unless you're wanting to go with 42" tires.

I'm running Currie 60s with 5.38s and switch between 42x13.50R17 and 44x13.50R20 tires.

Dave

 

[TEAMSLO]

4.88 on 38" Nitto TG, I would do the same if I had to start over.

 

[Keithbickford]

Looking to see if any other 392 owners that like to wheel are running 38 and have upgraded the gearing to 4:88 or 5:38. The factory 4:56 is on the way out

I’d be surprised if you needed to. Low range and a 392 should be unstoppable. But I’m not a hard core rock crawler. I’m more of the desert blaster.

 

[KTM300-152S]

38s with 4:56- works great - Rubicon, Deer Valley, Slick Rock and on the highway just fine.

 

[prodriquez]

I’m with @jeepguru on this one. I have 2 392s and run KMC beadlocks with Cooper STT Pros on each. One is on 37s and stock axles and the other is a 6,500 LBS beast on Currie Platinums (D70’s) and 40’s.

4.56 to maybe a 4.88 is as high as I’d go… but I doubt the juice will be worth the squeeze… but we’re talking about your money, so I’d totally go for it!

My big Jeep is on 4:88 and I’d only go as far as a 5.13 since I still drive to the trails. I’d love to regear to 5.38 and run a 42” or a 44”… but I wouldn’t be able to get the jeep in the garage

 

[OffRoadMedic392]

Sorry to hijack this thread, but has/is anyone else running 38"s on 3.73's for mostly daily driving on a "lighter" payload?

I bought my 392 used with 9,000 miles on it and It looks like its an XR due to the fender flares, and reinforced spare tire bracket, but I suspect its just a Non 392 because of the factory FOX shocks it has on. I won't truly know until I service the diff fluid and see what gears are inside.

Furthermore my buddy who has a Non XR 392, and runs his 40's on 3.73's as well as other heavy modifications. He tells me he has no complaints and see's 8th gear on the highway.

I'll see how the Jeep performs with the 38's, but if I'm not seeing any immediate concerns, should I even bother re gearing to 4.56 or 5.13 for a mostly daily driver with light offroading (I live in FL, worst off-road state ever) ?

 

[TEAMSLO]

I ran mine for a short time on 38s and stock 3.73, on the road, you'll just notice that it takes a bit more to get off the line. On the highway, it'll drop out of 8th quite often from wind, hills, passing.

On the dirt, found myself going into 4lo a bit more often that I expected for minor obstacles and such. Once switched to 4.88, seems to be the sweet spot for all.

 

[Earl 392]

Sorry to hijack this thread, but has/is anyone else running 38"s on 3.73's for mostly daily driving on a "lighter" payload?

I bought my 392 used with 9,000 miles on it and It looks like its an XR due to the fender flares, and reinforced spare tire bracket, but I suspect its just a Non 392 because of the factory FOX shocks it has on. I won't truly know until I service the diff fluid and see what gears are inside.

Furthermore my buddy who has a Non XR 392, and runs his 40's on 3.73's as well as other heavy modifications. He tells me he has no complaints and see's 8th gear on the highway.

I'll see how the Jeep performs with the 38's, but if I'm not seeing any immediate concerns, should I even bother re gearing to 4.56 or 5.13 for a mostly daily driver with light offroading (I live in FL, worst off-road state ever) ?

If you have the spats and reinforced tailgate bracket you probably have an XR with 4.56 . Go to a dealer and get a print out of your Jeep. A parts guy did that for me on a used vehicle I bought .
When I ordered my 23 I could not get the XR package . Stuck with 3.73 gears.

 

[GoetzC]

Sorry to hijack this thread, but has/is anyone else running 38"s on 3.73's for mostly daily driving on a "lighter" payload?

I bought my 392 used with 9,000 miles on it and It looks like its an XR due to the fender flares, and reinforced spare tire bracket, but I suspect its just a Non 392 because of the factory FOX shocks it has on. I won't truly know until I service the diff fluid and see what gears are inside.

Furthermore my buddy who has a Non XR 392, and runs his 40's on 3.73's as well as other heavy modifications. He tells me he has no complaints and see's 8th gear on the highway.

I'll see how the Jeep performs with the 38's, but if I'm not seeing any immediate concerns, should I even bother re gearing to 4.56 or 5.13 for a mostly daily driver with light offroading (I live in FL, worst off-road state ever) ?

I recently got a 2022 non XR 392 heavily modified with 40s on the stock axles with 3.73 gears. It rarely found it's way to 8th gear and not usually for long even on long flat highways. I regeared to 4.88 and it now finds 8th easily and is much less aggressive shifting during acceleration. Mine also has an aftermarket exhaust(magnaflow rockcrawler) that was borderline obnoxious prior to gearing. Now it's much more tame and doesn't scream during normal driving.

Not that it matters probably but I also increased from low 11mpg to mid 12s driving around town. I just finished the 500 mile breakin so have not done any long or drives yet but I'm very happy with the 4.88s. I had considered 5.13 and am glad now that I did not as it idles nicely at 70mph.

 

[prodriquez]

Sorry to hijack this thread, but has/is anyone else running 38"s on 3.73's for mostly daily driving on a "lighter" payload?

I bought my 392 used with 9,000 miles on it and It looks like its an XR due to the fender flares, and reinforced spare tire bracket, but I suspect its just a Non 392 because of the factory FOX shocks it has on. I won't truly know until I service the diff fluid and see what gears are inside.

Furthermore my buddy who has a Non XR 392, and runs his 40's on 3.73's as well as other heavy modifications. He tells me he has no complaints and see's 8th gear on the highway.

I'll see how the Jeep performs with the 38's, but if I'm not seeing any immediate concerns, should I even bother re gearing to 4.56 or 5.13 for a mostly daily driver with light offroading (I live in FL, worst off-road state ever) ?

A regear will roughly run around 3k to 4k, depending on your location.

From a performance perspective, the difference between 3.73 to 4.56 is about the equivalent of carrying vs. not-carrying 2 adult passengers. It is noticeable, but not dramatic…. Moving from 4.56 to 4.88, without changing tire size, would be almost unnoticeable.

Now some may argue with me on this… but I do have two 392s… so I’ll be the only one that’s right

 

[OffRoadMedic392]

If you have the spats and reinforced tailgate bracket you probably have an XR with 4.56 . Go to a dealer and get a print out of your Jeep. A parts guy did that for me on a used vehicle I bought .
When I ordered my 23 I could not get the XR package . Stuck with 3.73 gears.

I recently got a 2022 non XR 392 heavily modified with 40s on the stock axles with 3.73 gears. It rarely found it's way to 8th gear and not usually for long even on long flat highways. I regeared to 4.88 and it now finds 8th easily and is much less aggressive shifting during acceleration. Mine also has an aftermarket exhaust(magnaflow rockcrawler) that was borderline obnoxious prior to gearing. Now it's much more tame and doesn't scream during normal driving.

Not that it matters probably but I also increased from low 11mpg to mid 12s driving around town. I just finished the 500 mile breakin so have not done any long or drives yet but I'm very happy with the 4.88s. I had considered 5.13 and am glad now that I did not as it idles nicely at 70mph.

I will have to do that next time I go in and have them look up my VIN. .

That being said, after digging through these forums for a while since joining, I had read that the Ultimatum on knowing if you have an XR or not is if you have a Non XR you'll have FOX shocks w/ 3.73 , and the XR will have the Jeep performance shocks w/ 4.56.

Makes me wonder how mine ended up with all the XR trim pieces but with FOX shocks and unknown gears for now.

 

[guruman]

I will have to do that next time I go in and have them look up my VIN. .

That being said, after digging through these forums for a while since joining, I had read that the Ultimatum on knowing if you have an XR or not is if you have a Non XR you'll have FOX shocks w/ 3.73 , and the XR will have the Jeep performance shocks w/ 4.56.

Makes me wonder how mine ended up with all the XR trim pieces but with FOX shocks and unknown gears for now.

https://fcagroup.my.site.com/RAM/s/equipment-listing

Drop your Vin on this page and it'll list out your build sheet. My gear ratio is listed on page 8:

 

[Bhplumber]

I will have to do that next time I go in and have them look up my VIN. .

That being said, after digging through these forums for a while since joining, I had read that the Ultimatum on knowing if you have an XR or not is if you have a Non XR you'll have FOX shocks w/ 3.73 , and the XR will have the Jeep performance shocks w/ 4.56.

Makes me wonder how mine ended up with all the XR trim pieces but with FOX shocks and unknown gears for now.

My 21 XR had Fox shocks when I bought it at 9K miles