Brand New 2023 Rubicon Ecodiesel want to run 37 need to regear to 4.11 or 4.56?

[Sperger]

looking to run 37 K02 tires, not sure what lift yet, 2.5" Clayton or Mopar 2". Main thing is the gearing correct for factory like power or better. Thoughts? I have read a thread but was short and a couple of years ago. I read that the 3.73 are okay but laggy on power. Mostly mall crawler. Have dually for towing. might do some very light trails. No crawling. no overland.

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[RhinoJT]

I am running 4.56 with 40 inch Patagonias and KMC 17 inch desert beadlocks. Puts it within 100 rpm of factory and no issues with power. The 442 lb ft of torque really makes difference. Try it with the 37's, worst case you want more and go maybe 4.10s.

 

[whysoserious]

Is it a rock crawler, mall crawler, are you towing or loading a metric-butt-ton of overlanding "stuff" onto/into it?

 

[Sperger]

Is it a rock crawler, mall crawler, are you towing or loading a metric-butt-ton of overlanding "stuff" onto/into it?

Mostly mall crawler. Have dually for towing. might do some very light trails. No crawling

 

[whysoserious]

Well, then what @RhinoJT said. Throw those 37's on and see. A lot of folks on here did just that and are happy with the performance.

 

[Ecodiesel gladiator]

Depends on your driving style and preference. I like going fast and Immediately order a banks tuner and then regeared to 4.56 Dana spicers. Like the others suggested throw the 37” on and you will know if you want to regear or not. 4.10 gears would probably not be worth the couple thousands of dollars of expense , just my opinion. If you do long highway drives expect rpm to be higher around 2k @ 70mph. Overall I’m pleased with 4.56

 

[Escape.idiocracy]

looking to run 37 K02 tires, not sure what lift yet, 2.5" Clayton or Mopar 2". Main thing is the gearing correct for factory like power or better. Thoughts? I have read a thread but was short and a couple of years ago. I read that the 3.73 are okay but laggy on power. Mostly mall crawler. Have dually for towing. might do some very light trails. No crawling. no overland.

17x8.5 et0 wheel, 37” patagonias (36.75”)no lift- you can run around town fine and decide on your lift….
with the front disconnected and fully flexed out (stock) you will rub the inner liners front and rear… but this is disconnected and full flex… daily driving around town you will be fine- this will give you an idea for gearing and lift.
personally I am a fan of low center of gravity- low lift and maximize droop…. Gearing… super subjective. 3.73’s for running around town on a light 37” setup. Crawling, towing etc. I think you will want more, but again, that’s a decision you can make post tire install ?? 4.1 I don’t think is worth the cost>gain. 4.56 more on track. High elevation, towing, crawling 4.88’s

 

[Camaroboi13]

Pretty sure I have 3.45 gears in my JTOD with a 4.5” lift and 37s. I’ll never regear it, ever.

 

[NotSo Bright White]

I run 37 KO2’s with a Mopar lift and a 300 pound Harker Outdoor camper. I have never felt that it hasn’t had enough power with the diesel with the standard gearing.

 

[Jefe1018]

I’m on 37’s with stock gears and a mopar lift. I’m happy. I might regear eventually, but don’t feel it is an urgent need. It is nice enough for daily stop and go traffic, highway and in 4lo it is unstoppable. Of course, that is just my experience and opinion.

The lift kit… Mopar was $1,200 when I got mine, now they want close to $2,000. For that money go with Clayton or Metal Cloak.

 

[3VOLVE]

I’ve been running 37s on my JTRD for almost 20k with not issues on Mopar XR wheels +12 with no issues. I have towed a uhaul dual axle cargo trailer for several hundred miles with my cruise set at 72 mph and averaged ~21.5 mpg.

As stated by others, go ahead and throw them on and see if it works for you. No real need to upgrade.

 

[Rusty PW]

JTRD here with 4" lift and 37" tires. It runs great with the 3.73 gears. I've done some black trails with it too.

 

[Saltymedic]

I’ve been running 37s on my JTRD for almost 20k with not issues on Mopar XR wheels +12 with no issues. I have towed a uhaul dual axle cargo trailer for several hundred miles with my cruise set at 72 mph and averaged ~21.5 mpg.

As stated by others, go ahead and throw them on and see if it works for you. No real need to upgrade.

Agreed.

I didn't find a reason to regear even with towing. We live and tow throughout the Appalachians and it does just fine without it.

 

[Badunit]

I can't speak to to 3.0 but I regeared my 2015 6.7 Ram diesel so that it would hold high gear like it should. From factory it was geared to run at about 1200 rpm at 55 mph and, even with 800 lb-ft peak torque, it had to downshift on little hills because it was below the torque band. At 60 mph it would climb all the same hills perfectly with no downshifting. I determined all it needed was an additional 200 rpm to get the torque up to where it needed to be and become a totally different driving experience versus the anemic feeling it had. It spins a little faster than it needs to at 70+mph (it had plenty of power at those speeds before) but nothing crazy and my mpg is exactly the same as before and it feels strong everywhere.

So, my advice is to drive it a while, see if it works acceptably with the stock gearing, and, if not, try to determine the rpms required to make it perform like you want it to without going so far as to limit your top speed or kill your mpg. Base your choice of gears on that.

 

[Koolcarguy]

looking to run 37 K02 tires, not sure what lift yet, 2.5" Clayton or Mopar 2". Main thing is the gearing correct for factory like power or better. Thoughts? I have read a thread but was short and a couple of years ago. I read that the 3.73 are okay but laggy on power. Mostly mall crawler. Have dually for towing. might do some very light trails. No crawling. no overland.

I have 2 Jt diesels i Rubi 1 Sport s both on 37's Sport s has mopar lift Rubi has 3 inch lift . I pull my boat in the mountains of Wy and Co with zero issue my son has a 22 jtr diesel he runs 40's with 3 inch lift and went to a 4.63 gear from 4 wheel parts and loves the combination. We both off road and have no issue with power hope that helps

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