6sp MT Rubicon gearing

[ericnewcom]

Hello everyone.

I've been reading on here for a while, ordered and received my 2023 JTR MT. Overall I have to say I'm really happy with my new truck. It's taking on the role of my daily driver over my Tremor (It'll still be used for longer trips, trailer, and heavy hauling duties).

So on to my question. It seems geared really tall in 1st gear and reverse for a truck on 33" tires and 4.10 gears. At idle with the digital speedometer on the dash it fluctuates between 3 and 4mph mostly showing 3mph on level ground. You have to be very gradual for it to start moving on level ground at idle. Backing it into the garage with slight pitch of my driveway takes a lot of feathering / riding the clutch. It's way to fast with the clutch fully engaged to back into a single stall.

So this got me to thinking could there have been a mix up at the factory and I didn't get 4.10 gears? I looked under it last night and don't see any diff id tags or casting numbers that would signify 4.10. If anyone has information on how to identify the gears for the dana 44s please share. If anyone has the gear ratios for each of the 6 gears on the jeep 6sp mt I'd appreciate that as well.

I've read a post on here where someone said they think of the jeep transmission as a 4 speed with 2 overdrives and man would I love for it to be geared like my 75 f250 4speed. That truck at idle in 1st or reverse is about 1mph (could be less than 1mph it really crawls) and what I would expect an off road focused truck to act like. It'll back into my garage at a crawl at idle with no lugging or hesitation at all. I'll have to dig through some of my old documentation for the gear ratios for it's 4 speed but it has 4.10 gears so that is what has me thinking the JT should be more around the 1mph 2mph speed in first at idle.

Thanks in advance

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[bd100]

It was built correctly as designed. The gears are what the government mandates they must be. Three lower forwards gears, a direct drive, and two overdrives for a minor improvement in fuel efficiency at speed. I guess the JK had four forward, a direct, and one overdrive, which I would have preferred. There is no creeper first and no creeper reverse. The lack of a creeping reverse really hurts, and could be due to packaging limitations or the like.

I have a JT with 3.73 diffs. It's even worse than your 4.10s. I get to use 6th at 70MPH or so if not towing, and reversing up the driveway is bursts of feathering the clutch all the way.

A Centerforce clutch can help with the tendency to stall, and for offroading.

1st: 5.13
2nd: 2.63
3rd: 1.53
4th: 1.00
5th: 0.81
6th: 0.72
Reverse: 4.49

 

[NachoRuby]

I'm on 35s. I find first and second fine enough (and perfectly acceptable on stock 33s). But 3rd is quite long, and reverse is downright too long, of course exacerbated by my tires. But if it keeps the CAFE standards where they need to be, I'm ok with it. I'll probably eventually regear to 5.13, but I'm in no rush. Off-road, once you get in 4 low, it's more than fine in every gear. On road, the long 3rd and fourth are more than I'd like. But the worst is reverse, uphill. Sometimes i put it in 4 low to accomplish this without riding the clutch, if I don't have to turn sharp.

Eventually I'll regear. Then, if the stock clutch goes, I'll go aftermarket. Overall, I'm very happy with the truck, and I'll deal with it until I change some parts. I'm at 27500 miles now, most of that on the 35s.

 

[ericnewcom]

It was built correctly as designed. The gears are what the government mandates they must be. Three lower forwards gears, a direct drive, and two overdrives for a minor improvement in fuel efficiency at speed. I guess the JK had four forward, a direct, and one overdrive, which I would have preferred. There is no creeper first and no creeper reverse. The lack of a creeping reverse really hurts, and could be due to packaging limitations or the like.

I have a JT with 3.73 diffs. It's even worse than your 4.10s. I get to use 6th at 70MPH or so if not towing, and reversing up the driveway is bursts of feathering the clutch all the way.

A Centerforce clutch can help with the tendency to stall, and for offroading.

1st: 5.13
2nd: 2.63
3rd: 1.53
4th: 1.00
5th: 0.81
6th: 0.72
Reverse: 4.49

Thanks for the info. I found the gear ratios on my 75 which I used for a daily for 2 years until we had a bad storm and it blew a tree into it. Still derivable and I use it on the farm some but I have all the parts bought and just need to find the time to do a mild restore.

NP-435 Gear Ratios: (1,2,3,4,R): 6.69, 3.34, 1.79, 1.00,8.00

I understand cafe regs and all but the NP-435 is geared how a truck should be geared. I would gladly take the 1 -4 gears of the NP-435 in the jeep with the 5th and 6th for highway.

Oh and before anyone makes the comment all but 2 of my vehicles have been manual transmissions. I've had everything from sports cars to manual class 8 trucks. I think it is a mix of the relative tall first gear and low amount of torque from the 3.6 combined with the light flywheel that leaves me a little less than impressed with how I feel this truck should behave.

The main thing is I'm more confident it wasn't a gearing mix up. I plan to centerforce clutch when needed and re gear at some point. I plan to go to 35s when the 33s wear out and most likely will never go bigger than 37. I'm not sure if it'd fit in a 7' garage on 37 so it may stay on 35s until we move out to the farm in a few years.

 

[NachoRuby]

Thanks for the info. I found the gear ratios on my 75 which I used for a daily for 2 years until we had a bad storm and it blew a tree into it. Still derivable and I use it on the farm some but I have all the parts bought and just need to find the time to do a mild restore.

NP-435 Gear Ratios: (1,2,3,4,R): 6.69, 3.34, 1.79, 1.00,8.00

I understand cafe regs and all but the NP-435 is geared how a truck should be geared. I would gladly take the 1 -4 gears of the NP-435 in the jeep with the 5th and 6th for highway.

Oh and before anyone makes the comment all but 2 of my vehicles have been manual transmissions. I've had everything from sports cars to manual class 8 trucks. I think it is a mix of the relative tall first gear and low amount of torque from the 3.6 combined with the light flywheel that leaves me a little less than impressed with how I feel this truck should behave.

The main thing is I'm more confident it wasn't a gearing mix up. I plan to centerforce clutch when needed and re gear at some point. I plan to go to 35s when the 33s wear out and most likely will never go bigger than 37. I'm not sure if it'd fit in a 7' garage on 37 so it may stay on 35s until we move out to the farm in a few years.

Light dual mass flywheel + twin disk clutch, too. I think you'll get used to first gear. My only complaints at this point are 3rd being too long, and reverse. 1st and 2nd are about what I'd expect compared to other modern manuals (other than close ratio sports cars).

It's the DMF and twin disk clutch setup that take a while to get a good feel for on these jeeps.

 

[ericnewcom]

Light dual mass flywheel + twin disk clutch, too. I think you'll get used to first gear. My only complaints at this point are 3rd being too long, and reverse. 1st and 2nd are about what I'd expect compared to other modern manuals (other than close ratio sports cars).

It's the DMF and twin disk clutch setup that take a while to get a good feel for on these jeeps.

Yeah no doubt you can get used to the way it is but I still feel like it should be geared lower so you can maneuver around off road without having to go into low range. You shouldn't have to go to low range to back up a trailer or with a load either. I know jeep would never do it but it would be nice if they offered an off road focused manual with lower first and reverse as an option kinda like they offer 2 transfer cases.

 

[ericnewcom]

It was built correctly as designed. The gears are what the government mandates they must be. Three lower forwards gears, a direct drive, and two overdrives for a minor improvement in fuel efficiency at speed. I guess the JK had four forward, a direct, and one overdrive, which I would have preferred. There is no creeper first and no creeper reverse. The lack of a creeping reverse really hurts, and could be due to packaging limitations or the like.

I have a JT with 3.73 diffs. It's even worse than your 4.10s. I get to use 6th at 70MPH or so if not towing, and reversing up the driveway is bursts of feathering the clutch all the way.

A Centerforce clutch can help with the tendency to stall, and for offroading.

1st: 5.13
2nd: 2.63
3rd: 1.53
4th: 1.00
5th: 0.81
6th: 0.72
Reverse: 4.49

Do you happen to know of have a source for the JK 6 speed ratios? I'm wondering if it would be worthwhile to swap to a JK transmission...

 

[NachoRuby]

Yeah no doubt you can get used to the way it is but I still feel like it should be geared lower so you can maneuver around off road without having to go into low range. You shouldn't have to go to low range to back up a trailer or with a load either. I know jeep would never do it but it would be nice if they offered an off road focused manual with lower first and reverse as an option kinda like they offer 2 transfer cases.

On the Wrangler, they sort of do. You can get 4.88 gears from the factory there. Not offered on the gladiator, though. Would be nice.

 

[ericnewcom]

On the Wrangler, they sort of do. You can get 4.88 gears from the factory there. Not offered on the gladiator, though. Would be nice.

100% that'd be nice and would be what I would have ordered for sure.

 

[NachoRuby]

Do you happen to know of have a source for the JK 6 speed ratios? I'm wondering if it would be worthwhile to swap to a JK transmission...

For 1 and 2, the JK is no better. It's even longer in first. We have a JK too.

1st in the JK is 4.46 (compared to 5.13 for the JT and JL)
2nd is 2.61 in the JK (compared to 2.63 on JT/JL).
3rd is 1.72 (compared to 1.53)
4th is 1.25 (compared to 1.0)
5th is 1.0 (compared to .81)
6th is .8 (compared to .72)

Reverse is 4.06 (compared to 4.49).

The clutch is easier to drive on the JK, but overall, gearing is pretty similar until 3rd, and the transmission on the JT is much smoother and better, and doesn't shake, and reverse isn't stupidly next to 6th.


Your best bet is to regear. The JK transmission is even longer in first and reverse gears. 5th and 6th are a tad more useful on the JK. I don't see 6th much anymore on 35s, unless it's exceedingly flat.

 

[Geoarch]

I'm on 35s. I find first and second fine enough (and perfectly acceptable on stock 33s). But 3rd is quite long, and reverse is downright too long, of course exacerbated by my tires. But if it keeps the CAFE standards where they need to be, I'm ok with it. I'll probably eventually regear to 5.13, but I'm in no rush. Off-road, once you get in 4 low, it's more than fine in every gear. On road, the long 3rd and fourth are more than I'd like. But the worst is reverse, uphill. Sometimes i put it in 4 low to accomplish this without riding the clutch, if I don't have to turn sharp.

Eventually I'll regear. Then, if the stock clutch goes, I'll go aftermarket. Overall, I'm very happy with the truck, and I'll deal with it until I change some parts. I'm at 27500 miles now, most of that on the 35s.

I have essentially the same set up as Chad, but I live in a Mountain State. I’ll also eventually go to 4.88s. The JTR is still lower than my TRDPro. I’m ok with it.

 

[ericnewcom]

For 1 and 2, the JK is no better. It's even longer in first. We have one of those too.

1st is 4.46 (compared to 5.13 for the JT and JL)
2nd is 2.61 (compared to 2.63).
3rd is 1.72 (compared to 1.53)
Reverse is 4.06 (compared to 4.49).

The clutch is easier to drive on the JK, but overall, gearing is pretty similar until 3rd, and the transmission on the JT is much smoother and better., And doesn't shame, and reverse isn't stupidity next to 6th.


Your best bet is to regear. The JK transmission is even longer in the off-road and pulling gears..

Well that's a shame. Yeah I pretty much planned on a re gear anyway. Thanks for the info.

 

[bd100]

Glenwood Canyon west of Denver I was hauling a lot of weight and also towing 2000lb and was able to wind out first and second, but on some of the hills I was stuck around 45MPH in third because it couldn't accelerate any more. Red line in second turned into 3500ish in third gear. Gear spacing more like the JK would have been an advantage there. An extra gear before direct drive. Or the 8 speed auto, of course. But stick is so much more fun.

 

[AustinL911]

I'm on 35s. I find first and second fine enough (and perfectly acceptable on stock 33s). But 3rd is quite long, and reverse is downright too long, of course exacerbated by my tires. But if it keeps the CAFE standards where they need to be, I'm ok with it. I'll probably eventually regear to 5.13, but I'm in no rush. Off-road, once you get in 4 low, it's more than fine in every gear. On road, the long 3rd and fourth are more than I'd like. But the worst is reverse, uphill. Sometimes i put it in 4 low to accomplish this without riding the clutch, if I don't have to turn sharp.

Eventually I'll regear. Then, if the stock clutch goes, I'll go aftermarket. Overall, I'm very happy with the truck, and I'll deal with it until I change some parts. I'm at 27500 miles now, most of that on the 35s.

I'm surprised to hear that someone is actually OK with the stock 1st gear. I, too, am on 35s and find it to be awful.

I was pulling off the highway the other day to go hunting, and had to pull up to park on top of an embankment. Not super steep. I had it in first and it legitimately tried to stall out on the way up, in 1st! Kind of like you would expect if you were in too high of a gear and floored it, yet it doesn't really go anywhere. It was that, but I was in 1st/2WD. You would think it would spin the tires, but nope, just bogged down.

Personally (different strokes/folks), I'll be installing 5.13s sometime in the Spring along with a CF clutch. I cannot wait.

 

[NachoRuby]

I'm surprised to hear that someone is actually OK with the stock 1st gear. I, too, am on 35s and find it to be awful.

I was pulling off the highway the other day to go hunting, and had to pull up to park on top of an embankment. Not super steep. I had it in first and it legitimately tried to stall out on the way up, in 1st! Kind of like you would expect if you were in too high of a gear and floored it, yet it doesn't really go anywhere. It was that, but I was in 1st/2WD. You would think it would spin the tires, but nope, just bogged down.

Personally (different strokes/folks), I'll be installing 5.13s sometime in the Spring along with a CF clutch. I cannot wait.

Is yours a Rubi or Mojave with 4.1s? I've never had an issue with stalling on mine. But I know others have, so it's legit. I don't know why, but I don't have an issue taking off in first. I don't care for reverse (too long), and third is too long since I could max out the speed governor in 3rd. But 1st and 2nd are honestly fine for me. They are about the same as our JK, and really most others I've had.
Edit: I see yours is a Rubi too. Yeah, different strokes. I guess haha.

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