Regear to 4.56 from 3.73

[Mid13field]

Hi all,
I have a 2023 392 and recently upgraded to the 35” XR wheels/tires. She feels sluggish and just doesn’t have that pep that I had before—I lost that feeling like I was driving a race car. I’m planning on regearing to 4.56 but wanted to hear your thoughts regarding increase in performance and whether it’s worth it.
Thanks!
-Jeff

 

[Mid13field]

And as a follow-up, in the event that you’ve had issues outside of the grears/differential, has your dealership been lenient regarding your warranty?

 

[ramos1214]

I hate it and I am going down to 4.10!

 

[redbeard719]

My 2023 392XR came with the 4.56s. I swapped my XR wheels and tires for Method 703s with Nitto Ridge Grapplers in a 37x12.50.

4.56s have been good to me, I wouldn't consider any less.

 

[ParadigmDawg]

I run 3:73s with 37s and have no issues at all. Maybe I lost some low end torque but not enough to affect my rock crawling and it sure isn't slow on the street.

I planned to go with taller gears when I had it built but my shop said to go try it out on a few highway trips and a few off-roading trips and see what I think. I did a 200 mile road trip the next day and earned 4 BOHs. I haven't looked back sense.

If I had to get into the rear-end for some reason, I might consider changing but not just for kicks.

I am curious if you tested your "sluggishness", no real way to tell without using your Dragy.

 

[stumblinhorse]

If all you are going to is a 35” tire. 3.73 is totally fine. If you haven’t adjusted your tire size, you should do that next. Also depending on how long you had 33s, you need the ZF trans to re-learn shift points. You can force that with a JScan or pull the battery connections for overnight to clear ZF shift points.

4.56 is perfect for 37s. It is not worth the money and hassle for 35s.

 

[onfire392]

If all you are going to is a 35” tire. 3.73 is totally fine. If you haven’t adjusted your tire size, you should do that next. Also depending on how long you had 33s, you need the ZF trans to re-learn shift points. You can force that with a JScan or pull the battery connections for overnight to clear ZF shift points.

4.56 is perfect for 37s. It is not worth the money and hassle for 35s.

I could not tell hardly any difference going to 37's from 35's with the 4.56 It's a great match. Did have the speedo corrected by the dealership on the same day.

 

[KnoxRents]

You will lose some gear strength going to 4.56's but as long as you don't beat on it too bad (with the increased torque of the V8) off road, you should be fine. I ran a D44 with 4.56's for years without problems and then blew up a D60 with 4.56's after a couple seasons. Go figure.

I went with 5.13's in my JK but that 3.8 is a POS and needed it. 4.88's and 5.13's are too thin on a D44 for a 392 in my opinion but 4.56's should be thick enough and the pinion isn't stupidly small like the higher ratios.

You'll feel more pep but will rev higher on the highway but with the 8 speed, you should be fine.

 

[Mandrake]

My 2023 392XR came with the 4.56s. I swapped my XR wheels and tires for Method 703s with Nitto Ridge Grapplers in a 37x12.50.

4.56s have been good to me, I wouldn't consider any less.

Yeah, I have been thinking about this more and more. I was a little worried about the extra weight, but this thing has pretty good brakes.
Heck this thing rides around in 8th all day, I doubt the 37's would bother it much.
yeah I think you may have convinced me.

I can put the current 35's over on the Gladiator. It has 4.10's, I'll loose 8th gear until I get to the coast with it. I can live with that.

 

[Jaaack]

Jaaack's '23 392 Punk'n Metallic Build

2500 mile oil and T-case change. Yes I know it might be overkill on the T- case….. but I was curious to see the color and contents for my peace of mind…. and it‘s easy enough when already under there. This post is more for my own documentation at mileage intervals. ✌🏻

www.jeep392.com

Recently upgraded from the 3.73 to 4.56 gears. (Link above to all that was done at that time). I had put 37s on almost immediately and then after 4k miles of a few Colorado trips decided I wanted to. Wanted! It does feel stronger to me. Back to the way it felt with 33’s. Yes I know my highway MPG might suffer but I didn’t buy this vehicle for MPG.

 

[prodriquez]

Short answer: Absolutely not necessary but the 'fun-factor' will go up a tiny bit over the stock configuration. Your money and your call

Longer answer: Regearing is usually a good idea when your Jeep will no longer hold 8th gear on the highway. This commonly happens when you jump two tire sizes (from 33's to 37's/38's), add some weight to your vehicle (armor, a winch, recovery gear, etc.), or maybe you do lots of towing.

Regearing will cost you somewhere between $2,000 and $3,000, depending on location. If you do it, find a 4x4 shop that regularly does this sort of thing because this is precision work and you really want this done right!

Misc: I have two 392's, one is a dedicated rock crawler and the other is a dedicated mall crawler/husband recovery vehicle. I've done 33's, 35's, 37's, regeared to 4:56, upgraded to Currie Platinums (Dana 70's w/ 4:88's), and now run 40's. I never would have regeared if I had known that I would be moving to 1-tons a year later.

 

[Phil921]

I run 3:73s with 37s and have no issues at all. Maybe I lost some low end torque but not enough to affect my rock crawling and it sure isn't slow on the street.

I planned to go with taller gears when I had it built but my shop said to go try it out on a few highway trips and a few off-roading trips and see what I think. I did a 200 mile road trip the next day and earned 4 BOHs. I haven't looked back sense.

If I had to get into the rear-end for some reason, I might consider changing but not just for kicks.

I am curious if you tested your "sluggishness", no real way to tell without using your Dragy.

I'm in this same camp running 38's (37.76) with the 3.73s and every intention to go taller on the initial build list. But, the 3.73's run great with a bunch of highway miles and I've had no issues off-road. Certainly some performance loss from the line vs OEM paws, but that's not my jam anyway. Sticking with them unless/until axles come into the equation.

 

[ramos1214]

I'm in this same camp running 38's (37.76) with the 3.73s and every intention to go taller on the initial build list. But, the 3.73's run great with a bunch of highway miles and I've had no issues off-road. Certainly some performance loss from the line vs OEM paws, but that's not my jam anyway. Sticking with them unless/until axles come into the equation.

I regret going from 3.73 to 4.56! Now I am paying to go down to 4.10.

 

[84jeepjohn]

If all you are going to is a 35” tire. 3.73 is totally fine. If you haven’t adjusted your tire size, you should do that next. Also depending on how long you had 33s, you need the ZF trans to re-learn shift points. You can force that with a JScan or pull the battery connections for overnight to clear ZF shift points.

4.56 is perfect for 37s. It is not worth the money and hassle for 35s.

I'm in CO as well, and live right up against the mountains (so I'm ALWAYS going up and down LOL) On base I very rarely see 8th. but on 25 if I can stay out of it I can def keep in in 8th. How bad do you think the loss of power would be going to 37-38's?

 

[cgr]

I am also in the camp of running 37's with 3.73 stock gears. Granted, this is not my daily driver and I drive it like a race car - but I am happy with the setup. I did regear my JK before getting the 392. Just didn't think it was worth it to do on the 392. Hope this helps.
Chris

 

[stumblinhorse]

I'm in CO as well, and live right up against the mountains (so I'm ALWAYS going up and down LOL) On base I very rarely see 8th. but on 25 if I can stay out of it I can def keep in in 8th. How bad do you think the loss of power would be going to 37-38's?

You already have 4.56. For 37s that is ideal. You are not actually “losing” power. Certainly not as much as the elevation is taking. I wouldn’t give 37s with 4.56 gearing a second thought. I would be more concerned with steering components and wear…

 

[dgerb]

I am also in the camp of running 37's with 3.73 stock gears. Granted, this is not my daily driver and I drive it like a race car - but I am happy with the setup. I did regear my JK before getting the 392. Just didn't think it was worth it to do on the 392. Hope this helps.
Chris

I'm also running 37's on 3.73 gears, no problem. At this point in time, I'd rather spend the money on hydro...

 

[84jeepjohn]

You already have 4.56. For 37s that is ideal. You are not actually “losing” power. Certainly not as much as the elevation is taking. I wouldn’t give 37s with 4.56 gearing a second thought. I would be more concerned with steering components and wear…

Thats kinda what i figured. I think Jeep set the 392 up to just about run 37's stock.

 

[Mouse]

I have been running 35s (315) with 3.73 for two years now (summer months) and never really noticed a difference from stock 33s (285). The 392 also spoils me because i have been running my 2010 JK 3.8L on 35s for years with 3.73 gears so maybe my internal accelerometer is out of calibration. I had planned on regearing the 392 but for the kind of trails and trips I take I feel its no longer on my list of must haves. To each his own.

 

[DavyBoy]

I moved from 33's to 35's at 102 miles on day 2 of ownership. Now after almost 3 years (May 21st) and 18,430 miles with 3.73s, I am satisfied with this setup for both off road and street. However, I often feel like I have lost some zip, which is just not true, so I attribute it to me being so accustomed to the 392 power that it now feels common place. Most of us always want faster, bigger, etc., so a never ending cycle, but that's part of the fun of owning this beast.