JTRD on 37" what ratio 4:56 or 4:88

[yrwins]

Diesel.

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[Rusty PW]

Gas, they don't have diesel anymore. I wish they kept it.

5.13's with a diesel on 37's is overkill. You would need a 44" tire.

 

[CrazyCooter]

What lift and height you runnin?
My 3.73s on 35s tow 5k on stock Rubi good but would like to go 37s eventually

Lift? It's a net 2.5/3.0"......It gets complicated when I start playing with spring rates to achieve the result I'm looking for.

 

[Belcher24256]

EAV and the Dealer "MOPAR" is using 4:56. why they (EAV & Mopar) are not using 4:88 ? and the other hand I call Yukon and it tell me to used 4:88
and also don't forget about 4:11
I will not ever go to 40"

I am on the process of install Mopar 2" lift and Daystar 3/4" Comfort Ride Spacer.
clayton adjustable rear end track bar ( so I can put a spare 37" underneath )

tire are heavy 37x9.5x12 ta ko2 back rhino.

I used my jeep 35 % towing (rv 5,000). 15 % off road, (5% towing off road gravel Road )
50 % city and high.

current at 65-69 towing the rv getting 18-19 mpg.

My diesel Ruby is stock and cut the wheel pulling out to turn give too much fuel and it will roll the stock 33’s enough to get squirrelly before you can let up or stability management kicks in. Never done this intentionally but the day I bought was the first time I saw it. Given what I just said I can’t imagine any situation where a gear change would be needed for 37’s. Just my opinion for what it’s worth.

 

[salvino]

I forgot to mention I have the diesel version .

In that case 4:56 is probably plenty. I run 4:88s on 37s with the 3.6 and it’s plenty. It’s worth doing if you want max performance from the rig.

 

[tj3089]

I have a JTRD on 37's and a clayton 2.5" lift with 4.56 gears. If you tow a lot, don't lift it and keep it stock. My diesel would pull my 5000lb toy hauler without heat issues stock, but once I lifted it I started having overheating issues while towing.

I went into limp mode on my trip to CO this past year even with the 4.56 gears (summer in NM). We'll see if a tune helps lower EGTs. I love the power and acceleration with the gears, but the transmission short shifts unless you put your foot in it. I average 21-23 on highway trips without the trailer here in southern NM/West Texas.

 

[Hoss]

The 3.73‘s are perfectly adequate for 37” tires, you will hardly even notice a drop in fuel economy.

I saw someone else mention it, but getting a set of 4.10 takeoffs from a gas rubicon is a viable option. I would assume that they would fit without any issue.

 

[iav8]

This is from Exodus...
https://exodus4x4.com/jeep-regear
They have good videos and info regarding regears. Bubba’s other videos are a great watch too.

I had them give my diesel 4.56 gears after the lift and 37’s. Runs like a champ. Average around 19mpg and pulls a flatbed trailer no problem. I see all 8 gears.

 

[Zachanadandy]

This is from Exodus...
https://exodus4x4.com/jeep-regear
They have good videos and info regarding regears. Bubba’s other videos are a great watch too.

I had them give my diesel 4.56 gears after the lift and 37’s. Runs like a champ. Average around 19mpg and pulls a flatbed trailer no problem. I see all 8 gears.

You definitely have me beat on the mpg as I only average 14, on stock 4.10s and 37s from the gasser in the mojave. Still pulls a trailer just fine too. Personally I wouldn't bother regearing the diesel for 37s, and the people selling you the gears and install probably have a bit more motivation to tell everyone they need gears. I mean they recommend a regear for 35s in the diesel. I still see all 8 gears too.

 

[Chance575]

i have 4.88s and went bigger cuz I tow a travel trailer. Do it again I’d go 4.56.

 

[Sank]

I agree with all these guys. The most effect for gearing is in 1st gear. After that it just shifts at different points and then you wonder about how tall 8th gear is on the highway.

So if you want more gearing on the highway, just drive in 7th instead of 8th.

I have 37s and stock 3.73 and it. doesn't. matter. The Diesel just don't care.

The 3.73‘s are perfectly adequate for 37” tires, you will hardly even notice a drop in fuel economy.

I saw someone else mention it, but getting a set of 4.10 takeoffs from a gas rubicon is a viable option. I would assume that they would fit without any issue.

That isn't diesel advice, I'd roll the 3.73s and save that money for other things.

If you want to see what 4.56s are like at cruise, downshift a gear. 3.73s in 7th is nearly identical to 4.56 in 8th.

Diesels don't like rpm. Don't waste the money on a regear. 4.10s would be more optimal but that's a bunch of money for a small change. Just run it. If you want more power throw in a tune.

I have a pair of barely used 4:10 take off's sitting in the garage for when i Jump to 37"

You can get take off 4:10's pretty cheap from all the gas ruby guys doing swaps. I got mine from a friend who had very low milage and another friend who did the gear swap, so i knew their history. As a bonus they are OEM Dana gears

If you still want more gear, going to gasser 4.10s is definitely the best value. You get a 12% change going from 33" to 37" and you get a 10% change going from 3.73 to 4.10 (or 22% change going from 3.73 to 4.56, which seems like way too much, even for a gasser).

 

[Sank]

Also i think there's a thread in here somewhere about going to 4.88 gives you a smaller pinion gear or something. weaker supposedly. Somebody correct me here.

https://www.jeepgladiatorforum.com/...o-debate-go-4-88-gears-my-review.31785/page-7

 

[salvino]

This is from Exodus...
https://exodus4x4.com/jeep-regear
They have good videos and info regarding regears. Bubba’s other videos are a great watch too.

I had them give my diesel 4.56 gears after the lift and 37’s. Runs like a champ. Average around 19mpg and pulls a flatbed trailer no problem. I see all 8 gears.

Based on everything I have seen this chart is a little overkill unless you’re not planning to drive on the road maybe.

 

[caryt]

Just my take..getting 18-20 mpg's diesel well over 7Klbs, AluCab canopy camper on 3.73's and 38" Trail grapplers. When if I go to tons I'll swap to 4.56. I live in Carson Valley so everywhere is hills and mountains and I have a heavy foot. If I drive steady 65 for a long ways can get 21.

 

[JGR_Paris]

WOW.... that is why I love this forum.
thank so much for good information.
so it Is a BIG NO for 4:88 (I call Yukon and it tell me to used 4:88)

I narrow it down to two 4:11 or 4:56,
I think I will go with 4:56 because I do some towing and I think it will put me closest to factory



I was not thinking of a front track bar! do I need one

You will absolutely need an adjustable front track bar. I did both front and rear.

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