Best compromise gear ratio: 97 TJ, 4.0 automatic

Jun 30, 2016
20
4
#1
Just going to file this away for future reference at this point.
My daughter has a 97 TJ, 4.0 auto, 3.08 gears. What would be the best compromise gear ratio for her currently running 31's but maybe in the future going to 33's?
Her Jeep is a daily driver but she does enjoy doing trails here in Colorado. Occasional hiway use as it is a DD, but mostly just around town.
I'm asking because I keep an eye out for Dana 44's and if I ever got lucky and found one with the right ratio I'd probably snag it.
 
Dec 8, 2018
11
5
Greenville, SC
#4
I agree with 4.10 for 33" tires. I had a '97 with the 4.0 and auto - I put 4.10s and 33" tires on it initially. It was ok, but I later switched to 35" tires and wished I had gone with more gearing in the diffs.

I now have a 2004 Rubicon which came factory with the 4.10s and 31" tires. It has the 5 speed and I've decided as I go through my build that I'm keeping the 4.10s. My plan is 33" tires with the 3.5" MetalCloak short arm lift. I really considered going with 4.56 but I wanted to be able to drive it on the highway. My feeling is, for wheeling, the 5 speed with the 4.10s and 33" tires will be great and will keep it reasonable for any kind of highway driving (I no longer have a tow rig nor do I have a trailer...)

I found that for wheeling, the auto was a bit of a pig even on the 33s with the 4.10s - however, I was living in Utah and mostly using my rig as a trail rig (trailered for the most part). For daily driving, the 4.10s are probably fine (with the auto) especially if there are a lot of highway miles.
 
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Robb
Jun 30, 2016
20
4
#5
I wish my girl would just try to learn how to shift a manual, but no go what so ever. Pity but that's why I hunted for a long time trying to find her a nice 4.0 automatic.
I'll keep my eye open for anything 3.73-4.10 and consider myself lucky if I can find a deal.
 
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Robb
Jun 30, 2016
20
4
#7
What I meant my compromise was best for both. Currently have 3.08's and running 31/10.5 15's and MAYBE 33's in the future.
Just looking for a good compromise on what would work for both/either for now and in the future.
My daughter has dreams but who knows what will actually develop.
 

Rob5589

Certified video trained differential rebuilder
Supporting Member
Aug 29, 2016
5,883
5,425
W Sacramento, Kalifornia
#8
What I meant my compromise was best for both. Currently have 3.08's and running 31/10.5 15's and MAYBE 33's in the future.
Just looking for a good compromise on what would work for both/either for now and in the future.
My daughter has dreams but who knows what will actually develop.
That was my point. Why spend 1500+ dollars for something that will work well for 31's but not so well for 33's? 33's are a whole different animal than a 31. Increased weight, width, resistance, and rolling diameter. A "compromise" would be finding some used axles with 3.73, which is a very common ratio, and go from there.
 

astjp2

TJ Enthusiast
Aug 22, 2018
368
165
Utah and Alaska
#9
Well you could think outside the box, leave the 3.07, install a tummy tuck, drive it for a while, and then work on deciding what tires you may want. I went with 34's and 4.11 in my YJ but my tranny does not have an overdrive so it works good for me. I have lots of clearance and lots of ability to do what I want. My wifes's old TJ had 235's on it, we went to all kinds of trails and had a blast for a daily driver. We just knew that we would not be doing anything rough with DOT tires.
 
Jul 16, 2018
25
16
Gadsden
#10
I can speak from experience thanks to the advice I received on this site. Re-geared my 2000 4.0 auto with 285/70/17 (33s) to 4.10s and it is by far the best modification I've made to my TJ. Perfect manners for all my driving conditions. Obviously it's not a compromise setup but one tailored for 33s. Not sure if that helps any.
 

Rob5589

Certified video trained differential rebuilder
Supporting Member
Aug 29, 2016
5,883
5,425
W Sacramento, Kalifornia
#12
Go with the 3.73's you will probably find in the used D44's your looking for, then when you decide to go to the 33's you can re-gear to 4.56 in those axels without new carries needed.
4.56 and 33's is a bit too deep on the 3 spd auto, unless you are willing to keep hwy speeds down to around 60. 70 is 3300 in drive