This wasn't in the brochure...

[AVGeek99]

Yea I have a 2.0 and almost didn't comment because of it but I see this so much with all of them that my comment was for the guys not knowing and yes I should have lead with what I had, to clarify for those people.
The amount of difference I would see by re gearing isn't worth the cost to do it. I have had other guys, mainly JK guys, drive it and tell me I had no reason to re gear and one of them actually does the re gear in Jeeps all the time. It's my first Jeep and so naturally when I see these comments I'm thinking I need a re gear. But after I did the lift and still had the 33s on it, it handled like shit and was very top heavy feeling. After moving up to 37s and adjusting the Taser Mini to reflect the tire upgrade it went back to feeling like stock off the parking lot. When I travel the mountains with other JKs, who have been re geared, I have to slow down so they can keep up to the point it's annoying.

I only made the comment because some guys on here and facebook jeep groups will be insistent on a re gear when it's not always necessary, it seems to be a knee jerk reaction.

When you have a Rubicon it's a lot easier to get by without a regear because 4.10s are already 2 or 3 steps shorter than the other trim levels with their 3.45s. But if you have 3.45s, especially with the manual, if you go to 35s and especially bigger, regearing is going to make a world of a difference both on and off road.

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[AVGeek99]

That was always my worst towing scenario: flooring it at redline in 3rd, then trying to give it a breather by putting it in 4th, but that just bogged it down to the point where it wasn't doable, so you have to slam it back into 3rd and listen to it scream. Then repeat over and over while it slows down more and more. Those gears are just too damn tall.

I think the biggest problem with the 6MT is the distance betwen 3rd and 4th.

 

[Zandcwhite]

To be clear, all my comments below are assuming a manual transmission.

Your 2nd sentence proves the point I was trying to make. You can get by with larger tires on stock gearing, as long as you shift "as early and often as the automatic does". The automatic is always shifting, just as it's designed and programmed to do; and it does it very well. I like driving a manual but shifting that often would take a little bit of the fun out of it.

A Rubicon with it's 4.10s could get by with 37s, in the flat lands, but I certainly wouldn't want to drive it. I drove mine with 35s for two years and it was perfectly acceptable, but I am VERY happy that I regeared to 4.88s for 37s. I drove on my 35s for 5 months with the 4.88s before getting the 37s. I thought the 4.88s were too short for 35s, I honestly didn't like it. When I got the 37s it was a huge improvement. With that big a difference moving from 35s to 37s on 4.88s, I can only imagine how bad the 37s would have been with 4.10s.

I would never drive any of the other trim levels with their 3.45s on anything but stock tire size. I drove a JK Sahara with stock 3.21s with 35s for a couple years. In 6th, it struggled to hold 65 on level ground with no headwind. Add any amount of headwind or incline and you were losing speed. 3.45s in the JL are step up from 3.21s, but 5th and 6th in the JL are significantly higher than the JK. The JLs one saving grace for use with taller diffs is 1st gear is significantly shorter.

I wasn't trying to argue that there's never a case for a regear, I just don't think the manual needs the extreme end of gearing that some argue. I've seen guys recommend as low as 5.13s for 35s. In my opinion those guys really just want an automatic. If your goal is to row through the gears once and spend the rest of your drive in 1 gear I guess that works but 1st gear becomes nearly useless on the street at that point. As discussed 5-6th are damn near the same. With gearing that low you could take off in 2nd, skip 5th altogether, and enjoy your 4 speed I guess.

 

[AVGeek99]

I wasn't trying to argue that there's never a case for a regear, I just don't think the manual needs the extreme end of gearing that some argue. I've seen guys recommend as low as 5.13s for 35s. In my opinion those guys really just want an automatic. If your goal is to row through the gears once and spend the rest of your drive in 1 gear I guess that works but 1st gear becomes nearly useless on the street at that point. As discussed 5-6th are damn near the same. With gearing that low you could take off in 2nd, skip 5th altogether, and enjoy your 4 speed I guess.

Yeah, that's crazy. For the few months I drove mine with 35s and 4.88s, I didn't like it. It was just too short for flat lands driving. I could never get it to shift smoothly. As soon as I got my 37s, I was in heaven, sorry for the rhyme. Everything just works so much better and shifting is much smoother now.

If I lived in CO and was constantly driving through the mountains, I would want 5.13s in combination with 37s, probably not 35s. We were in the San Jauns in late July and the long mountain passes were tough. To hold 45 I had to keep it in 3rd gear, 4th gear would lose speed. I wouldn't like that if I was driving those passes every day.

 

[Save The Manuals!]

Today I got to deliver a new 2024 Sport S (in Tuscadero) automatic through the hills and twisties of Southern Missouri. I paid close attention to the shifting and the tach. Yep, it shifted a lot--sometimes downshifting two gears on steeper climbs. Most shifts were at about 2500 rpm, but the downshifts on the steeper hills let it scream at 3500 rpm. Wish I knew exactly which gear it was using at a given time, but I'm glad I had the opportunity to get an idea of how to manage my manual more effectively.

 

[AVGeek99]

Today I got to deliver a new 2024 Sport S (in Tuscadero) automatic through the hills and twisties of Southern Missouri. I paid close attention to the shifting and the tach. Yep, it shifted a lot--sometimes downshifting two gears on steeper climbs. Most shifts were at about 2500 rpm, but the downshifts on the steeper hills let it scream at 3500 rpm. Wish I knew exactly which gear it was using at a given time, but I'm glad I had the opportunity to get an idea of how to manage my manual more effectively.

You can check what gear the Auto is in by pulling the shifter to the left into manual mode. Then the D on the dash cluster will change to Mx, with x being the gear it is in. Just don't forget to put it back in Drive. It wont hurt anything if you leave it in manual. But the next time you come to a stop it will autmatically shift down into 2nd, but then wont shift as you speed up. You'll need to shift manually or push it back over to Drive.

 

[CarbonSteel]

Couldn't resist (owner's manual; job description).

It's the lack of torque (260 lb-ft) in combination with it starting higher in the RPM range. Gearing would help, but is not a panacea.

 

[CarbonSteel]

It's the nature of the high revving v6 that doesn't produce enough torque in the first place combined with the torque being produced higher in the RPM range.

Fixed it for you. If the 3.6L produced >400lb-ft versus 260lb-ft this would be a non-issue.

 

[Ratbert]

Fixed it for you. If the 3.6L produced >400lb-ft versus 260lb-ft this would be a non-issue.

And, of course, the manual wouldn't be able to handle that much torque.

 

[azwjowner]

I think the biggest problem with the 6MT is the distance betwen 3rd and 4th.

Bingo. But the deeper you regear, the larger the divisor is that closes up the distance between those two gears. The distance between 3rd and 4th drove me nuts with 3.45 gears. I regeared to 4.56, the distance between those gears closed up, and it’s a million times better. I’m still on 32s. I advocate for regearing as deep as you can stand for highway travel.

 

[Steph1]

Gears may be the answer in your case but my 21 JLU Rubicon with 37s has never had that problem, even in the real mountains. I see other people telling others to re gear when you move up in tire size all the time and in a lot of cases it's very unnecessary.

Say most Jeep guys until they actually regear or test drive a regeared Jeep… I know, I was one of them. Then they see the light and finally understand what those that suggest regearing are talking about. The hard to describe tremendous satisfaction one experiences when his Jeep turns the 35-39 inch tires with the same ease it did the puny stock tires is one of those Jeep things that some couldn’t understand, until they experience it.

 

[grimmjeeper]

Double overdrive. Huh. Who would've thought?? I wonder what the point of that is?

The double overdrive just means you need shorter (higher number) gears in the axle.

The transmission, axle gears, and tire size are one big equation to balance with how the engine performs.

The 3.6 doesn't make good low end torque (basically the opposite of a diesel). On flat roads you can take advantage of lower RPMs. But hills like they have in Iowa require some shifting. Either that or just leave it in 5th.

Back when I lived in eastern IA with my manual JK, I would routinely leave it in 5th. When I regeared to match bigger tires (4.56 with 315/70R17) I was able to leave it in 6th a lot more.

 

[CarbonSteel]

And, of course, the manual wouldn't be able to handle that much torque.

True, but it seems the same applies to the automatic which only masks the problem of not enough torque, but couldn't handle >400 lb ft either.

Jeep's powertains need a serious upgrade.

ZF8 = 500Nm max torque (369 lb ft)
AL6 = 468Nm max torque (345 lb ft)

 

[Zandcwhite]

And, of course, the manual wouldn't be able to handle that much torque.

The manual won't handle the full torque of the 3.6L. The fix for exploding clutches was to derate the already under powered V6.

 

[73TAWM]

Say most Jeep guys until they actually regear or test drive a regeared Jeep… I know, I was one of them. Then they see the light and finally understand what those that suggest regearing are talking about. The hard to describe tremendous satisfaction one experiences when his Jeep turns the 35-39 inch tires with the same ease it did the puny stock tires is one of those Jeep things that some couldn’t understand, until they experience it.

Maybe so, but so not worth it to me.

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