Regear 3.07 to 3.73/4.10?

[TJRD4]

Looking for confirmation on the ratio before ordering. 97 TJ sport, AX-15, 4L 6 cyl, NP231, 30x9.5s. Currently have ~200k miles on the 3.07 gears/bearings with some bearing issues so need to rebuild. For the regear the goal is to improve performance/mpg, etc. Not too much off roading besides dirt roads/logging trails. Plan to keep the 30x9,5s and maybe... 31x10.5s but very unlikely. Jeep is otherwise super stock; no towing.

Using the grimjeeper calculator, at 70mph in 5th gear, 3.73 - 2310, 4.10 - 2539 rpm.

Thank you. Thoughts?

 

[Vulture]

I did the 307 to 410 change on my 01 TJ, (NV 3550, 4.0) and really happy with the results, but I don't have any plans to go larger than 33" tires. It does great on the highway and 1st gear low range it creeps along nicely. I live in Indiana so no mountains or high altitude 02 starvation to deal with.

 

[inkedrose]

My last TJ was on 31's with 3.73, did pretty well even in the Rockies. If I remember right, 31's w/4.10 is what Rubicons came stock with

 

[deadbeat son]

Living in Colorado, I was very happy with 4.56 and 31s with the NV3550 in my '02. You should avoid 3.73 and go with a minimum of 4.10 if you're going through the work of rehearing. I would encourage 4.56 if you're seriously considering 31s, but 4.10s should be fine for 30x9.50 and will be passable with 31s. I would hate 33s with 4.10s.

 

[OldBuzzard]

Many of us regear for 2900 to 3000 RPM at 75 MPH. It sounds high, but it's just about right for highway cruising.

 

[TJRD4]

Thanks all! For 30s at 75 mph. the 4.10 gets just under 2800 rpm. So we will go with that!

 

[Harold&Cat]

I believe you will be happy with the 4.10 gears . I ran 3.73 gears with 30 , 31 and 32 inch tires over the last 11 years . With the 42rle transmission and 3.73 gears, I couldn't utilize overdrive until 60 mph . I am now running 4.88 gears with 33 inch tires .

The Jeep is very happy