Another Stock Mojave on 37s (Manual)

[Gregj]

For brand choice of the gears you can’t go wrong with Dana Spicer as they make the axles for Jeep.
Gregj

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[piroman683]

Magnuson supercharger helps remedy high altitude struggles

 

[Bbannongmu]

I'll probobly suffer through my first trip with the 4.10s. I don't think I'll have many future trips out west with the truck (typically motorcycle) so it will stay mainly in Florida. Leaning towards the 4.88s or maybe 5.13s most likely depends on what I find a good deal on. I passed on a new-in box set of 5.38s the other day but hadn't done enough research into the companies.

Any brand recommendations or things to avoid? I've seen some issues with Yukon around these parts.

Avoid Yukon at all cost!!!!! I went with Spicer after my Yukon pinion exploded at 50k miles.

 

[bryanklay]

I am running a 2020 overland model with true 37s and 4.56 gears and do have a slight problem climbing hills fully loaded, but i am quite happy with what i have. I have done a lot with what i have. could i have gone with a 4.88 yes, but i was not thinking that way. the 4.88 is a great move and if i had thought longer on this idea the answer is yes i would have gone 4.88. it is to late now because i have 34,000 mile on this set.

 

[Jteakus]

I don't know how you supercharged folks keep from scattering the 3.6

 

[Partysub]

I did half of white rim last year (the wash towards the end had over 5 feet of water on it) and have my reservations for June of this year to hopefully run the whole thing. I have a mojave (auto) on 37s and stock gears on a 2 inch spacer lift and never really hit anywhere where wheel clearance was an issue. The stock gears were fine with 4 people in the truck pulling a small scout trailer. I was only in 4lo once and that was going up Murphys hogback. What campsites did you get?

 

[Bjeepz]

For brand choice of the gears you can’t go wrong with Dana Spicer as they make the axles for Jeep.
Gregj

Yes you can literally buy factory 4.56 and 4.88! Both are factory JLU Rubicon options. Somebody will correct me if these don't fit our JT's!!

 

[Ding gus]

I am running a 2020 overland model with true 37s and 4.56 gears and do have a slight problem climbing hills fully loaded, but i am quite happy with what i have. I have done a lot with what i have. could i have gone with a 4.88 yes, but i was not thinking that way. the 4.88 is a great move and if i had thought longer on this idea the answer is yes i would have gone 4.88. it is to late now because i have 34,000 mile on this set.

Great feedback all around. I'm convinced a regear is in the near future, will definitely have it done if/when its time for a lift.

I did also discover the TPMS sensors that were installed are not compatible (not surprised) so I do need to swap some newer ones in. I think I will take that opportunity to switch over to the fifteen52 wheels. I like the raceline wheels but shiny things are hard to keep shiny.

 

[JulesAo]

I have a Mojave on 37s right now and the stock 4.10 gears. I'm about ready to pull the trigger and go to 4.88. I'm not sure I need to go to 5.13 being in Florida, and I'm not sure I will necessarily go to bigger tires. I dream of going to bigger offroad events locations, but wondering if the 4.88 won't be plenty to do that.

 

[Mukluk25]

Bear in mind as you get past central Texas on your way to Moab you'll be gaining altitude a good portion of the way. Moab is at around 4,000 ft but you'll have places in Colorado where you exceed that by quite a bit before you drop down into the valley. On the stock gears with 37s, hoo boy, you'll learn about 3rd & 4th gear.

You’ll be able to walk faster over the passes. At least the scenery is awesome.

 

[Jaydebe]

I dunno about some stories as accounted; but my experience was beyond expectation for 37s on a stock rig.

Here's a pic of doing 75 accelerating up an onramp and in 5th gear. I had to take the pick because I had the locked light come on and needed "proof" of the issue existing for the dealership.
And another pic showing how much was in the wind packed out. The the tent and bikes sucked down another 2ish mpgs.

I had a stock JTR on 37's (although I did pick wheels and tires based on weight also) 103lbs for the Methods mounted with Grabber ATXs.
Factory mpgs: 21ish (all mpgs around 55-70pmh) Over 70, minus 1-2mpgs for ea. below.
37s: 19.5
Packed down: 17.5

It was an auto, but calibrated with a Tazer; all was pretty Ok.
I live on a resort at 4.5k, and surrounded by passes about 3-4.5k in every direction with no issues.
Yes, it was a hit to the mpgs, about 2mpgs on flat highway at close to posted limits and 3-4mpgs less at 80+ or when loaded down.

Several XC trips to Az, Utah, and WC, and more. Worse issues, the flats of Tx at 80+. 6th gear was the best it would do and mileage was about 13.5.

Crossing passes though, even coming home through Co; no issues and always stayed up with traffic. Even loaded with rack, tent, 2 bikes and gear needed for off grid 30-day trip.

All said, I plan in the long term to add 4:88s in if I go 37s again.
1) I'll be using heavier tires
2) 4:88s so I can easily drop to 35s if I want and not be over geared.

Haven't driven a manual JT to be educated on one.

 

[Gregj]

Ok, 5th gear in an auto is like 3rd in a manual, so yes 3rd gear will accelerate pretty good too. You can’t compare auto to manual, that’s apples and oranges.
Gregj

 

[piroman683]

I don't know how you supercharged folks keep from scattering the 3.6

The challenge with the 3.6 is the damn cam followers since they can prematurely wearout. I've dealt with this 3 times (once at 57k before the supercharger, and 2 mote times after). What i've concluded, so far, is that you need to be over 3k rpm's or at 2500 and below. at 2800 is when the oil pressure increases, but if you are constantly floating between high and low pressure then the pressure driven mechinism in the cam follower wears out and you get valve tick.

I've raced in Baja with the magnuson with 0 issues, blew my rear passing raptors in the whoops, and the clutch and trans were always fine.

The other advantage here is the manual trans do not need an trans cooler in the front so you have better cooling for the supercharger and engine. Not to mention no need to reprogram shift points like an auto

 

[JT1]

The challenge with the 3.6 is the damn cam followers since they can prematurely wearout. I've dealt with this 3 times (once at 57k before the supercharger, and 2 mote times after). What i've concluded, so far, is that you need to be over 3k rpm's or at 2500 and below. at 2800 is when the oil pressure increases, but if you are constantly floating between high and low pressure then the pressure driven mechinism in the cam follower wears out and you get valve tick.

I've raced in Baja with the magnuson with 0 issues, blew my rear passing raptors in the whoops, and the clutch and trans were always fine.

The other advantage here is the manual trans do not need an trans cooler in the front so you have better cooling for the supercharger and engine. Not to mention no need to reprogram shift points like an auto

Close... the oil pressure changes right at 3K too, when the high lift cam switch happens.

I'm on 37s and 5.13s with the 6spd. 90% of the miles on this thing have been 70-80mph, which is 2500 to 2800 rpm. Oil pump switchover happens right at 85mph.

 

[piroman683]

Close... the oil pressure changes right at 3K too, when the high lift cam switch happens.

I'm on 37s and 5.13s with the 6spd. 90% of the miles on this thing have been 70-80mph, which is 2500 to 2800 rpm. Oil pump switchover happens right at 85mph.

so yes and no, pressure starts increasing at 2800, its a setting in the software to activate the solenoid). However it takes a few rpms to get up to full pressure. There is also a slow pressure decay once under 2800 (once it turns off). My initial intent was to say stay away from 2800 with margin, so keeping it at 3k or 2500k keeps the pressure constant regardles of the actual pressure. (i.e. minimize on/off of the solenoid)

You mentioned the 3.6 scattering apart with SC's, do you have any technical details?

I've only heard of a few instances and some of them being from running a larger pulley. I'v taken data logs and saw max boost around 8psi. I know others have swapped out the rods as those were noted as the weak point for higher boost applications.

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