Diesel Gladiator owners with upgraded gearing ONLY please...

[TheSolarWizard]

Stock gearing 39” KM3s CA to NM & back

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[M390]

Stock gearing 39” KM3s CA to NM & back

Mine with stock 3.73’s and 35’s wouldn’t get that mileage. I averaged 20-21 on the highway, same as I do with 4.56’s and 35’s.

 

[Vtur]

Run from Austin to W TX. Flat road, zero wind, cruise set at 75.
This is with 4.56’s and Yokohama 35’s. Gearing calculator I used was dead on for speed/rpm with 4.56’s. Everything is properly adjusted for gearing, tire size, and shift points with my Tazer.

What tires psi are you running? Your mpg appears kinda low.

 

[M390]

What tires psi are you running? Your mpg appears kinda low.

35” Yokohama G003’s at 30 psi on 17” Warn Moonsaults
Same mileage I got with 3.73s. I do have a winch/bumper, Fab Fours rocker protection, Roll n Lock tonneau, and carry quite a few tools. Banks Derringer set on 4.

 

[NC_Overland]

Interesting thread, I don’t have a diesel but have had Dodge trucks in the past, couple things I would consider, this diesel is not like a diesel from 10 years ago, it revs way higher, 4500 or so as I recall, also if you can run 37” tires with no penalty I would think Jeep would have installed the 3.45 ratio in the non Rubicon diesels with the 31” tires, they are going for best economy after all.

What Gladiator has 31s? A sport? My Overland came with 32.2” tires. The Mohave has 33s. Genuinely curious.

 

[kilroy173]

What Gladiator has 31s? A sport? My Overland came with 32.2” tires. The Mohave has 33s. Genuinely curious.

My California edition, which is basically a Sport S came with 245/75r17s with is basically a 31.

 

[SaplingT]

Well after getting my lift and 37's installed and driving it around in the Pacific Northwest hilly areas all weekend I will definitely be regearing. It just feels like it's fighting to stay on top and you have to modulate the throttle to encourage it to downshift etc. This to me is not great and a regear is on the list of items to get scheduled as soon as I can find the parts! Probably going right to 4.56 since you can't get 4.30 for the2022 Rubicon axles.

 

[Jefe1018]

I’ll chime in, on 37’s there is no need for gears. If you think so, you haven’t driven a diesel on 37’s.

Here is my drive home from Idaho back to Vegas in October when I picked her up with 37’s. I now average 19 in mostly city driving and can still pull my 3800lb boat uphill with cruise on 70 on the steepest hills in the vegas valley without busting a sweat. I doubt 4.10’s would really give you a better bang for your buck.

Not sure if my experience counts as experience but nonetheless, OP might
be smarter than me.

 

[SaplingT]

Gearing debates are literally the thing that might break the internet . Mine is a diesel and I feel the opposite. I want the truck to shift effortlessly and not run around under load at 12-1300 RPM hoping it shifts down. With the hills here in the Seattle area it is a stark difference stock to 37's. Even on a diesel.

 

[Gladiator Overland]

I’ll chime in, on 37’s there is no need for gears. If you think so, you haven’t driven a diesel on 37’s.

Here is my drive home from Idaho back to Vegas in October when I picked her up with 37’s. I now average 19 in mostly city driving and can still pull my 3500lb boat uphill with cruise on 70 on the steepest hills in the vegas valley without busting a sweat. I doubt 4.10’s would really give you a better bang for your buck.

Not sure if my experience counts as experience but nonetheless, OP might
be smarter than me.

I’ve chimed in on this previously. I’d say you haven’t had enough time behind the wheel. I was under the same impression. Then stubbornly was like oh a tube will just make up the difference. Although the tune greatly helped and is manageable. You honestly need regearing, not that it isn’t something one can get away with putting off or dealing with the downfalls. So much left untapped here in the powerband that a proper 4.56 would greatly improve.

 

[Jefe1018]

I’ve chimed in on this previously. I’d say you haven’t had enough time behind the wheel. I was under the same impression. Then stubbornly was like oh a tube will just make up the difference. Although the tune greatly helped and is manageable. You honestly need regearing, not that it isn’t something one can get away with putting off or dealing with the downfalls. So much left untapped here in the powerband that a proper 4.56 would greatly improve.

You think an ecodiesel JT needs 4.56 gears to run 37's correctly?

This silly argument might just break the internet.

I've got over 10,000 miles on the clock, about 3,000 towing and plenty of 4L time - it is fine. 4Lo is almost unusable at this point - only for the steepest and the slowest of crawling.

Edit: I'm not arguing that it wouldn't 'help' - I'm arguing that the money, time and effort would be for a negligible gain and likely even a hit on MPG.

 

[Jefe1018]

Gearing debates are literally the thing that might break the internet . Mine is a diesel and I feel the opposite. I want the truck to shift effortlessly and not run around under load at 12-1300 RPM hoping it shifts down. With the hills here in the Seattle area it is a stark difference stock to 37's. Even on a diesel.

I don't know, I've driven this thing everywhere. Towed my boat to Texas and back from Las Vegas. I've been to Idaho and back, long steep hills everywhere I go. Not a damn complaint.

 

[Vtur]

I think it's all come down to driving styles. Some prefer to drive it like an SUV off the line and others might just taking it easy off the line. For me, i knew right away, within a couple miles that i needed to regear. I lost 2.5 mpg with the 37s and gained .5 mpg back after regeared.

 

[Gladiator Overland]

You think an ecodiesel JT needs 4.56 gears to run 37's correctly?

This silly argument might just break the internet.

I've got over 10,000 miles on the clock, about 3,000 towing and plenty of 4L time - it is fine. 4Lo is almost unusable at this point - only for the steepest and the slowest of crawling.

Edit: I'm not arguing that it wouldn't 'help' - I'm arguing that the money, time and effort would be for a negligible gain and likely even a hit on MPG.

You are hilarious. A Jeep owner arguing about time and money when it comes to a Jeep.
I am not going to argue about this when dealing with the gearing. I am staying from my experience when dealing with my rig, my weight, and running 37” myself. Two areas need to be worked on. Have tried to go the tune route with GDE and although it helped. Regearing is needed simple and period. As well as better braking performance, ie upgrade. I won’t argue about spending money on a Jeep. I’m beyond this in my mods equaling At least the costs of the Jeep in it. I didn’t get a Jeep to save money. That’s what a Hyundai is for and a car that gets 40+mpg. :laughs: I constantly stay in 7gear when before I would have been in 8gear. I can’t say 100% as I haven’t done the gearing yet. It’s set for the future. But will comment on past experiences. I will not only regain drivability with shifting, low pedal response; IE off-road ability and ability to climb large inclines. But will see mileage increases on Hwy and elsewhere where it would kick into 8th where I am constantly seeing 6th/7th now. Drivability is the game. I didn’t say it was necessary as neither are running 37s in a Jeep. Both work fine but at what cost in performance and drivability? Drop your costs argument as it’s nonsense as one could do the gear change themselves with a little help and education.

 

[Jefe1018]

You are hilarious. A Jeep owner arguing about time and money when it comes to a Jeep.
I am not going to argue about this when dealing with the gearing. I am staying from my experience when dealing with my rig, my weight, and running 37” myself. Two areas need to be worked on. Have tried to go the tune route with GDE and although it helped. Regearing is needed simple and period. As well as better braking performance, ie upgrade. I won’t argue about spending money on a Jeep. I’m beyond this in my mods equaling At least the costs of the Jeep in it. I didn’t get a Jeep to save money. That’s what a Hyundai is for and a car that gets 40+mpg. :laughs: I constantly stay in 7gear when before I would have been in 8gear. I can’t say 100% as I haven’t done the gearing yet. It’s set for the future. But will comment on past experiences. I will not only regain drivability with shifting, low pedal response; IE off-road ability and ability to climb large inclines. But will see mileage increases on Hwy and elsewhere where it would kick into 8th where I am constantly seeing 6th/7th now. Drivability is the game. I didn’t say it was necessary as neither are running 37s in a Jeep. Both work fine but at what cost in performance and drivability? Drop your costs argument as it’s nonsense as one could do the gear change themselves with a little help and education.

That was a long winded and kind of snarky response to only admit you’ve still not done the change but really think it’ll help because you have money to burn because Jeep.

No one is ‘arguing’. Let me know how the gear change affects your drivability when you do go through with it.

Admitedly I am planning for likely 4.10s when I go 40s in the next year or two. At that point I’ll want a daily driver other than the JT, what Hyundai gets 40mpg? Ha!

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