Sponsored

6MT + 4.88 + 35s; anyone do it?

loudog3114

Well-Known Member
First Name
James
Joined
Jan 24, 2020
Threads
6
Messages
79
Reaction score
66
Location
Boston
Vehicle(s)
No
80 mph in 6th is about 2700 rpm. I didn’t check 85, but suspect it would still be about the limit before you’d push to stage two. Not sure what the diff is to 5.13 either. I’d guess you could 80 with 5.13 and not trip into stage two. But probably not much more with 37’s and a 6 speed manual.
Roger. Appreciate it. Might go with 5.13 anyway since most cruising is done at 80 or below.

I really wonder how much of a concern that high psi mode should be anyway. That motor is supposed to be ultra reliable. The only redeemable characteristic.
Sponsored

 

Bbannongmu

Well-Known Member
First Name
JTR.Spartacus
Joined
Jan 18, 2020
Threads
26
Messages
1,874
Reaction score
2,155
Location
Earth
Website
m.facebook.com
Vehicle(s)
2020 Jeep Gladiator Rubicon
Build Thread
Link
Occupation
Certified Emergency Manager
Vehicle Showcase
1
37s. M/T, stock gears. Not great. Not terrible but I think I’ll be re gearing in the future.
 

loudog3114

Well-Known Member
First Name
James
Joined
Jan 24, 2020
Threads
6
Messages
79
Reaction score
66
Location
Boston
Vehicle(s)
No
37s. M/T, stock gears. Not great. Not terrible but I think I’ll be re gearing in the future.
As somebody who has had 37s on stock gears for almost a year; it is terrible. 4th gear to maintain speed up hills terrible.
 

cgflyer

Well-Known Member
First Name
Steve
Joined
Mar 15, 2019
Threads
15
Messages
526
Reaction score
372
Location
Lorton, VA
Vehicle(s)
2020 Gladiator Rubicon MT, 2013 Ford Focus ST
Occupation
United States Coast Guard
IMHO, regearing for 35's (if you have 4.10's) is a waste of money. I ran 35's on my '12 JKR and have 35's on my '20 JTR now and no issues...yes, 6th gear is a dog, but it is meant to be a dog. It is overdrive. It is not a passing gear and it is not a hill climb gear or a towing gear. I have 32,000 miles on mine btw, got the 35's mounted 2 days after I took possession. I actually love 3rd gear in 4lo, only use 1st and 2nd in 4lo for hill descents. Haven't needed to climb anything super steep yet, but what I have climbed, 3rd in 4lo was perfectly adequate. I actually find 4hi at low speeds annoying because 1st is too much and 2nd isn't enough and so you are constantly working the clutch and break.

Now I do not plan on doing much crawling and drive a lot of highway and am building my rig for overlanding...I just ordered 37's and plan to drive stock for a few months, but I actually want my 6th gear RPMs to stay close to stock (I rarely drive faster than 70mph, there are a lot of speed demons on here). If/when I re-gear, I will almost definitely go with 4.56.

Again, simply my opinion, but I have about 120,000 miles in a 3.6L on 35's and did a lot of muddy and off-road parks and sand driving in my JKR. So far I have done some sand driving and some trail driving in the JTR (one trail badge so far...kinda hard to find them on the east coast)
 

Jt-wrx

Well-Known Member
First Name
Blake
Joined
Dec 24, 2019
Threads
18
Messages
671
Reaction score
459
Location
eh
Vehicle(s)
20 sport s 6spd
the tow gear, 1:1 is 4th and with 4.88's on 37's running just under when the 3000-ish rpm second stage oil pump comes on will be right around 62 mph fyi

on a longer trip this past summer with approx 3800 lbs of trailer, gear, humans on board or behind our 5150 lbs of jeep, we ran 4th on way back fighting wind, 11.9 mph, on way there with tail winds we were able to run 5th most of the time at about 71 mph with much more tolerable revs

4.56 would still be pretty good, and lightyears better tha 4.10 or 3.73, 3.73 could get me barely by on 35's but as soon as i went to 37's that was it for 3.73. If you're jeep is a heavy pig to start with a ton of gear bolted on to it, winches, steel bumpers, all that overland gear, fenders, skid plates etc. etc. then weight will be a factor to consider imo.

My jeep i went super lightweight sporty 'stock plus' clean agile build on sport s hardtop, i am essentially stock with mopar lift, stock wheels which weigh nothing compared to anything aftermarket, falken 37x12.5 mt's and that's it...overland running boards and an access cover tonneau, stereo upgrade, maybe 100 lbs added...you can add 100 lbs with just a bumper...mine is tall, skinny, and lightweight and because so it's a very sporty truck to drive. I look at the amount of stuff people bolt onto these rigs and cringe at all that added weight. So take that for what it's worth.

Could i get away with 4.56, yes probably, could most of the rigs i see being built up get away with 4.56 on 37's (manual transmission)...i'd suggest you better start with 4.88's. I don't see hardly any rigs on 37's built as simply or lightweight as mine.
 

Sponsored

Golvach

Member
Joined
Nov 10, 2020
Threads
1
Messages
8
Reaction score
68
Location
Dallas, TX
Vehicle(s)
2021 Gladiator Overland
I've got a 2021 Overland, 2" Mopar lift with 35" Nitto Trail Grappler MTs. Regearing to 4.88 on the 26th. Will post update after regear.

Current situation: After the lift & 35s, while still on the 3.73 gears, I lost most use of 5th and 6th gear, unless on very flat road with zero wind. Gas mileage dropped horrendously as well, especially on the highway. I'm having to open the throttle all the way to maintain speed in 6th, and often find myself still losing speed if there is any elevation change or wind--so I'm burning through fuel and not getting any power out it. At 70mph in 6th, I'm currently right at 2,000 RPMs.

I debated back and 4th between 4.56 and 4.88. The risk of going with the 4.56 gears is that my performance improves, but it still feels a little doggish on the highway and I wish I went bigger... also would potentially need to regear again if I ever went with bigger tires. With the 4.88s, there's a risk a might over-gear a bit, but it wouldn't neccessarily cause any negative issues other than running a little higher rpms. The shop I'm using is expecting that I'll be at 2600-2700 rpms at 75mph in 6th with 4.88s. That's a little higher than I would prefer, but wouldn't be bad for the vehicle in any way. Plus I think it will give me much more passing/climbing power on the highway.

Like everything in life, it's just a series of trade-offs.... Anxious to see how it turns out.
 

Puttyandnapalm

Well-Known Member
First Name
D
Joined
Aug 11, 2019
Threads
17
Messages
330
Reaction score
303
Location
Cumberland, MD
Vehicle(s)
2020 Hydro blue gladiator overland
Occupation
Casino
I have a MT with 35's, and went from 3.73 to 4.56. This is a hell of a lot better both off road and on the highway. I should have done 4.88's to be honest as I'd have a little more pep in the desert, but I'm still happy with the 4.56

Here is my approach to this. I looked at what tire/gear ratio was used on the max tow (4.10 with 245/70/17's). Then I looked at what i have (315/70/17 with 3.73) so the new ratio to match max tow is 4.79. Well, no one makes 4.79 so the closest was 4.88 (.09 away) or 4.56 (.23 away). I opted for the 4.56 because it seemed like the best tradeoff for what I do which is 75% highway, 20% desert prerunning, and 5% trail crawling. How it would be better off roading with 4.88's but I can always swap later if I really need to. I have literally zero interest in going to larger tires.
any more thoughts on the 4.56 vs 4.88? I live in a mountainous area and the 3.73s are killing me with even the stock 32’s in my 6mt. I’d like to get up to a 34 tire and think I’d go with a 4.56....
 

hjdca

Well-Known Member
Joined
Oct 27, 2019
Threads
9
Messages
1,639
Reaction score
2,324
Location
Southern California Mountains
Vehicle(s)
Jeep Gladiator Rubicon manual Sting Gray
Build Thread
Link
any more thoughts on the 4.56 vs 4.88? I live in a mountainous area and the 3.73s are killing me with even the stock 32’s in my 6mt. I’d like to get up to a 34 tire and think I’d go with a 4.56....
I have a JTR manual with the 4:10s. The 4:10s are still not enough gear for 33s. Just figure it this way. The stock gears on the JTR with 33s should have been 4:56s. That would have been perfect for the 33s. Now with 35s, go 4:88s, the installer will probably try to talk you out of 4:56s anyway. 4:88s are perfect for 35s. I am installing 37s, and I am going 5:13s.

Note: There is a reason why people debate 4:88s or 5:13s for 37s... It is because 4:88s are still a tad tall for 37s -- especially in mountainous areas like we live in.
 

Puttyandnapalm

Well-Known Member
First Name
D
Joined
Aug 11, 2019
Threads
17
Messages
330
Reaction score
303
Location
Cumberland, MD
Vehicle(s)
2020 Hydro blue gladiator overland
Occupation
Casino
I have a JTR manual with the 4:10s. The 4:10s are still not enough gear for 33s. Just figure it this way. The stock gears on the JTR with 33s should have been 4:56s. That would have been perfect for the 33s. Now with 35s, go 4:88s, the installer will probably try to talk you out of 4:56s anyway. 4:88s are perfect for 35s. I am installing 37s, and I am going 5:13s.

Note: There is a reason why people debate 4:88s or 5:13s for 37s... It is because 4:88s are still a tad tall for 37s -- especially in mountainous areas like we live in.

Went ahead and did the 4.56 regear and added Rubicon takeoffs (32.7). 5th and 6th are issuable again even in the mountains. I was considering upgrading to a 34” tire, but it feels good now with the just the rubi stock 285/70/17.
I thought about 285/75/17 to get up to a 33.8”, but maybe I should have done the 4.88. Oh well. I’m very happy with the regear, other than the price. All manuals should have come with the 4.10s minimum IMO.
 

Bbannongmu

Well-Known Member
First Name
JTR.Spartacus
Joined
Jan 18, 2020
Threads
26
Messages
1,874
Reaction score
2,155
Location
Earth
Website
m.facebook.com
Vehicle(s)
2020 Jeep Gladiator Rubicon
Build Thread
Link
Occupation
Certified Emergency Manager
Vehicle Showcase
1
As somebody who has had 37s on stock gears for almost a year; it is terrible. 4th gear to maintain speed up hills terrible.
I went with 5.13 gears. Much better drivability. In the break in period now. Can’t wait to try this off road and towing soon. #JTRSPARTACUS
 
Last edited:

Sponsored

Jt-wrx

Well-Known Member
First Name
Blake
Joined
Dec 24, 2019
Threads
18
Messages
671
Reaction score
459
Location
eh
Vehicle(s)
20 sport s 6spd
I went with 5.13 gears. Much better drivability. In the break in period now. Can’t wait to try this fog road and towing soon. #JTRSPARTACUS
Great update, when you're done break-in do another one with every 5 mph rpms up to 80 and put it here, i'll mirror your vid with the 4.88's numbers at the same speeds. Should be a great resource to help people choose.
 

Bbannongmu

Well-Known Member
First Name
JTR.Spartacus
Joined
Jan 18, 2020
Threads
26
Messages
1,874
Reaction score
2,155
Location
Earth
Website
m.facebook.com
Vehicle(s)
2020 Jeep Gladiator Rubicon
Build Thread
Link
Occupation
Certified Emergency Manager
Vehicle Showcase
1
Great update, when you're done break-in do another one with every 5 mph rpms up to 80 and put it here, i'll mirror your vid with the 4.88's numbers at the same speeds. Should be a great resource to help people choose.
Will do. Be a great side by side. Getting close to the 500 miles. I have an appt scheduled for next week for the installer to change diff fluid and inspect (required for gear warranty). For me it came down to 5.13 due to towing and off-road.
 

Jt-wrx

Well-Known Member
First Name
Blake
Joined
Dec 24, 2019
Threads
18
Messages
671
Reaction score
459
Location
eh
Vehicle(s)
20 sport s 6spd
Will do. Be a great side by side. Getting close to the 500 miles. I have an appt scheduled for next week for the installer to change diff fluid and inspect (required for gear warranty). For me it came down to 5.13 due to towing and off-road.
We can get nerdy, since i have sport-s i run tazer jl mini and adjusted tire height setting so my 80 mph speedometer was bang on to this gps online speedometer https://www.zpeed.in/ i ran on my phone. I think i needed to use 36.44" tire height to get it bang on. Your fancy model may have a way of accurizing this without having to jump through the hoops i did? ;) But then we'd be as apples to apples accurate as one could get for a couple speedo corrected JT 6-spd's on 37's with 4.88's and 5.13's. :)
 

Bbannongmu

Well-Known Member
First Name
JTR.Spartacus
Joined
Jan 18, 2020
Threads
26
Messages
1,874
Reaction score
2,155
Location
Earth
Website
m.facebook.com
Vehicle(s)
2020 Jeep Gladiator Rubicon
Build Thread
Link
Occupation
Certified Emergency Manager
Vehicle Showcase
1
We can get nerdy, since i have sport-s i run tazer jl mini and adjusted tire height setting so my 80 mph speedometer was bang on to this gps online speedometer https://www.zpeed.in/ i ran on my phone. I think i needed to use 36.44" tire height to get it bang on. Your fancy model may have a way of accurizing this without having to jump through the hoops i did? ;) But then we'd be as apples to apples accurate as one could get for a couple speedo corrected JT 6-spd's on 37's with 4.88's and 5.13's. :)
I have a Tazer mini and used it to adjust my tire size and my speed checked out with a gps app. I can check again using your same app. I’ll PM you to coordinate the video stuff
 

Bbannongmu

Well-Known Member
First Name
JTR.Spartacus
Joined
Jan 18, 2020
Threads
26
Messages
1,874
Reaction score
2,155
Location
Earth
Website
m.facebook.com
Vehicle(s)
2020 Jeep Gladiator Rubicon
Build Thread
Link
Occupation
Certified Emergency Manager
Vehicle Showcase
1
I have a Tazer mini and used it to adjust my tire size and my speed checked out with a gps app. I can check again using your same app. I’ll PM you to coordinate the video stuff
working on this. coming soon
Sponsored

 
 



Top