Regear or Not

[grimmjeeper]

I have a gladiator on 35's with 3.73 it sees 8th on flat ground and gets an average 19mpg, it's also just fine offroad, now im not pounding it on a vertical rock face but it's climbed 38degrees without much trouble. I think it would be perfect with 4.10. We also have a jlu xr with 4.56 on 37's and it's fantastic, I wouldn't even consider changing them. Also have a 2 door jl on 33's with stock 3.45's motor is a 2.0 turbo. It climbs grades in 8th. Sometimes I just dont understand where some think that jlu needs 5.13's on 37's.

Try rock crawling 37s with a manual transmission at high altitude.

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[Zandcwhite]

I have a gladiator on 35's with 3.73 it sees 8th on flat ground and gets an average 19mpg, it's also just fine offroad, now im not pounding it on a vertical rock face but it's climbed 38degrees without much trouble. I think it would be perfect with 4.10. We also have a jlu xr with 4.56 on 37's and it's fantastic, I wouldn't even consider changing them. Also have a 2 door jl on 33's with stock 3.45's motor is a 2.0 turbo. It climbs grades in 8th. Sometimes I just dont understand where some think that jlu needs 5.13's on 37's.

I think a huge part of it is people going from extremely under geared like 3.45s and 35s to less extremely over geared and thinking it's better so it must be right/perfect. Running 35s and 3.45s is the same as running 4.10s and 42s. Obviously not the best combo. Conversely going to 5.13s for 37s is way too much gearing especially if you drive western freeway speeds regularly. That's the gearing equivalent of 3.45s and a 25" tire. We've also run more than 8 gearing and tire combos across 2 JLURs and my JT and another dozen plus across other off road vehicles. The 4.56 gears and stock 35s felt over geared on the freeway. 4.10s and 37s with the 3.6L could use a little more gear but I wouldn't go past 4.56s. The 2.0t was great on 4.10s and 37s. 5.38s and 38s was terrible. In 8th gear by 40mph, worse mpg on the freeway, slower 0-60 with the 2.0t as it had to shift an extra time to get there. Currently running 4.56s and 39s on the JLUR and 4.10s and 37s on the JT. If regearing was free I would go 1 step deeper on both. 4.88s for 39s and 4.56s for 37s. At $3k locally for a regear I won't waste the money.

 

[c20040215]

Try rock crawling 37s with a manual transmission at high altitude.

5.13 gives you 100+ crawl ratio which is really nice not gonna lie.

 

[Beach Nut]

Seems the 4.56 gears are the sweet spot for 35s…

 

[Beach Nut]

The XR with the 35” tire package gives you 4.56 from the factory…any thoughts?

 

[Zandcwhite]

5.13 gives you 100+ crawl ratio which is really nice not gonna lie.

Overkill paired with an auto. Its not a Toyota with a 22re, a manual, and 80hp. The stock XR 84-1 crawl ratio is more than enough even on 39s.

 

[c20040215]

Overkill paired with an auto. Its not a Toyota with a 22re, a manual, and 80hp. The stock XR 84-1 crawl ratio is more than enough even on 39s.

That's your opinion. Mine is I wish I had 120 crawl ratio.

 

[Zandcwhite]

The XR with the 35” tire package gives you 4.56 from the factory…any thoughts?

The vast majority of JLs come from the factory with 3.45s and 32s...and don't have a 4-1 transfer case. That's the same gear ratio as running 37s and 4.10s. I'd argue Jeep was more likely to put optimal gearing in the most common models. Even if you think the xr is the perfect combo (which felt overgeared at freeway speed) that only puts you at 4.88s for 37s.

 

[grimmjeeper]

Seems the 4.56 gears are the sweet spot for 35s…

When I had 35s, 3.73 was a great combination. But I have a 3.0 diesel. The 392 is also good with tall (lower number) gears than the 2.0 or 3.6.

There is no one univeral "perfect gear ratio" for any JL. Not only does it depend on the engine and transmission, it depends on how you use it.

If you never leave the flat lands of flyover country, you will be happy with taller gears. If you never do heavy rock crawling you'll be happy with taller gears. Spend a lot of time in the mud, taller gears are better.

On the other hand, when you regularly get up at high altitude, shorter gears are nice. Especially if you don't have a turbo. If you crawl big rocks a lot, shorter gears are a must. If you have a manual transmission that doesn't hide the inadequate low end torque of some of the Jeep engines, you want shorter gears. Towing benefits from shorter gears too.

Fortunately, the Jeep has a great set of automatic transmissions. They do a good job of allowing for a range of axle gears to be "good enough" for most people. And if you're happy with the gears and tires you have, enjoy them.

But the next person to come along may have a very different Jeep and may use it in different ways, so what works for you isn't always the best choice for someone else. And that's what is great about the Jeep. Everyone can customize their own to how they use it.

 

[Beach Nut]

Question still new to the community and learning here, but I currently have 2024 Willys with the 4.10 &33s. Above someone stated you can do 37’s with the 4.10’s. I live in south Texas so beaches and occasional crawling are in line. Can I get away with 37’s if not I have been looking at 35’s. I went to the Jeep Academy back in April and the Jeep rep said I could get away with 35’s and possibly 37’s with a lift. I’m just trying to prepare for my build. I was thinking 2.5 lift with 35’s but heck if I can do the 37’s with a 3.5 that would be even better.
Thanks for any feedback.

I’m running the Clayton 2.5 Overland Kit on my Sahara with 35s…plenty of clearance…however, with this kit, all you need is the 3.5 springs and possibly shocks to go higher. My 2.5 yielded a bit over 3” from stock…it handles great on light to moderate off road situations! Bilstein 5100 shocks.

 

[mrtm1970]

I think a huge part of it is people going from extremely under geared like 3.45s and 35s to less extremely over geared and thinking it's better so it must be right/perfect. Running 35s and 3.45s is the same as running 4.10s and 42s. Obviously not the best combo. Conversely going to 5.13s for 37s is way too much gearing especially if you drive western freeway speeds regularly. That's the gearing equivalent of 3.45s and a 25" tire. We've also run more than 8 gearing and tire combos across 2 JLURs and my JT and another dozen plus across other off road vehicles. The 4.56 gears and stock 35s felt over geared on the freeway. 4.10s and 37s with the 3.6L could use a little more gear but I wouldn't go past 4.56s. The 2.0t was great on 4.10s and 37s. 5.38s and 38s was terrible. In 8th gear by 40mph, worse mpg on the freeway, slower 0-60 with the 2.0t as it had to shift an extra time to get there. Currently running 4.56s and 39s on the JLUR and 4.10s and 37s on the JT. If regearing was free I would go 1 step deeper on both. 4.88s for 39s and 4.56s for 37s. At $3k locally for a regear I won't waste the money.

Thanks for the info and input!

I will say just going to 37s on the 4.11 gears, I also have the Pedal Commander and I have no issue/loss power wise, acceleration wise or any and see 8th gear all the time

 

[Zandcwhite]

That's your opinion. Mine is I wish I had 120 crawl ratio.

Some people want to go REALLY slow. The problem is if you're trying to get there via axle gears you'll be going slow on the freeway too. I've yet to find an obstacle where I needed more gearing than 1st gear, 4LO, even with 4.10s but you do you. With 5.38s and the 101-1 crawl ratio I found 1st gear was almost useless. Even if I wanted 120-1 I'd go atlas 4 speed tcase and 4.56s so I could still drive cross country comfortably at 85mph.

 

[grimmjeeper]

The vast majority of JLs come from the factory with 3.45s and 32s...and don't have a 4-1 transfer case. That's the same gear ratio as running 37s and 4.10s. I'd argue Jeep was more likely to put optimal gearing in the most common models. Even if you think the xr is the perfect combo (which felt overgeared at freeway speed) that only puts you at 4.88s for 37s.

You'd be wrong.

Jeep put inadequate gears in the base models to meet CAFE standards driving on an unrealistic test loop.

 

[grimmjeeper]

Overkill paired with an auto. Its not a Toyota with a 22re, a manual, and 80hp. The stock XR 84-1 crawl ratio is more than enough even on 39s.

I'm sorry that someone talked you into overgearing your Jeep. But that doesn't mean you have to overcompensate the other direction. And it certainly doesn't mean that short gears aren't useful to others.

I regularly used deper than 100:1 crawling in Moab with a 3.6 and manual transmission. I needed that to keep from stalling or bouncing too fast through the rocks.

 

[grimmjeeper]

Some people want to go REALLY slow. The problem is if you're trying to get there via axle gears you'll be going slow on the freeway too.

Not necessarily. I suppose if you have some unnatural aversion to running the engine over 2,000 RPM you wouldn't like the freeway RPMs. But this isn't 1978 anymore. Modern engines (except the diesel) do great at higher RPMs. You shouldn't be afraid of revving the engine a little.

I've yet to find an obstacle where I needed more gearing than 1st gear, 4LO, even with 4.10s but you do you. With 5.38s and the 101-1 crawl ratio I found 1st gear was almost useless. Even if I wanted 120-1 I'd go atlas 4 speed tcase and 4.56s so I could still drive cross country comfortably at 85mph.

Feel free to do what makes you happy.

But suggesting that your preferred setup is perfect for everyone else is simply disingenuous at best. Just because you don't do something doesn't mean others don't or shouldn't. It's potentially dishonest, much like the person who talked you into 5.38s.

Just because you don't do something doesn't mean others don't or shouldn't.

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