Gear ratio for daily driver

Christoph0315

Christoph0315

Member
Joined
Jun 14, 2020
Messages
27
Location
RVA
Hey y'all,

I have a 2002 tj with NV3550 Trans (4.0l and 5 speed man).
I'm planning to keep the Jeep forever, so what would you guys recommend me to do in terms of front axle/gear ratio? Engine is done and interior as well. I'll focus for the next phase on axle and drivetrain before the final chapter, bodywork outside
I have a stock engine, with Edelbrock cyclinder head 1.5 Rocker Roller and I'm planning to install a boosted SC next winter. The jeep runs on 31inch tires.
I drive to work 30 miles each way but we use it for beach, dessert and fun. I haven't been on trails yet but will sooner or later go as well.
currently my biggest issue is, my front differential is leaking and I'm always between 4th and 5th gear on the highway.

What can you guys recommend me, considering that I'll have tons of stuff in mind and don't want to touch things twice?

best!
 
In addition to the advice you get here, be sure to check out this resource:
https://wranglertjforum.com/threads...angler-tj-lj-and-other-re-gearing-faqs.17063/
Also, play around with this calculator:
http://grimmjeeper.com/gears.html
I recommend subtracting 1 inch from your tire size before putting it in the calculator. That will account for the deflection of the tire under load.

Most manual owners like to target around 3000 RPM at 75 mph. On 30s or 31s, a little lower is also acceptable, as the rolling resistance is lower.
 
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Steel City 06 said:
In addition to the advice you get here, be sure to check out this resource:
https://wranglertjforum.com/threads...angler-tj-lj-and-other-re-gearing-faqs.17063/
Also, play around with this calculator:
http://grimmjeeper.com/gears.html
I recommend subtracting 1 inch from your tire size before putting it in the calculator. That will account for the deflection of the tire under load.

Most manual owners like to target around 3000 RPM at 75 mph. On 30s or 31s, a little lower is also acceptable, as the rolling resistance is lower.
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Thx,
I read for hours the first link but couldn't find the answers to my case. I'm looking for a decent plug and play solution and since my differental is now leaking anyway I may consider a front axle swap and do the rest later. Again, just not really sure what's the right way and brand to go yet.
I'm aiming for 200hp when things are finished and want the appropriate drive train. 3000rpm at 75 sounds wonderful. Currently the 5th gear is kind of useless. Wouldn't mind shorter.
 
4:56 , 4:88 at most. I have 4:56 with 33" tires and that engine/transmission combination.

You'll need to fill out an application and submit to The Forum regearing committee.,. The cut off day is the 15th for September.
 
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I would gear to 4.10 if you are pretty confident you will be sticking with 31's. If you might go to 33's and are OK with some higher RPM's on the highway for now, 4.56 might be a better bet. I really enjoyed my 4.56's with 33's.
 
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There's enough difference in gearing for 31's vs. 33's that I'd only pay to regear once you know for sure what size tire you'll end up with. With your transmission 4.56 is optimal for 33's, 4.10 is optimal for 31's. 4.10 will "work" for 33's too but I had that combination for a while and it was undergeared enough that I did not like it for my area that has hills and mountains. If I knew where "RVA" was I'd be able to give a little more solid advice on that.
 
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Jerry Bransford said:
There's enough difference in gearing for 31's vs. 33's that I'd only pay to regear once you know for sure what size tire you'll end up with. With your transmission 4.56 is optimal for 33's, 4.10 is optimal for 31's. 4.10 will "work" for 33's too but I had that combination for a while and it was undergeared enough that I did not like it for my area that has hills and mountains. If I knew where "RVA" was I'd be able to give a little more solid advice on that.
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Good post. Location is so important. In South FL where I’m from there are no hills and you can definitely get away with less consideration toward re gearing. In Atlanta where I live now there is a definite need for a re gear if running larger than stock tires.
 
Jerry Bransford said:
There's enough difference in gearing for 31's vs. 33's that I'd only pay to regear once you know for sure what size tire you'll end up with. With your transmission 4.56 is optimal for 33's, 4.10 is optimal for 31's. 4.10 will "work" for 33's too but I had that combination for a while and it was undergeared enough that I did not like it for my area that has hills and mountains. If I knew where "RVA" was I'd be able to give a little more solid advice on that.
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RVA is Richmond, Virginia but I'm most likely moving next year near your area. Dana point or San Diego, not sure yet...
 
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Jerry Bransford said:
With many of the most popular desert and mountain trails out here you'll want 33's at a minimum. For 33's I'd go 4.56.
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This post is indicative of a man with deep experience.

Even though we may be on different operating planes, I can respect his viewpoint.

(Chris, can I get double points for this, I've worked on it for 24 hours)
 
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alright alright alright 4.56 it is than.
what parts do I need to order?
and speaking about my leaking differntial, what would you guys do on the front axle? I just dont want to put any money in that garbage oem piece if im going to change it soon anyway.
thx again!
 
Christoph0315 said:
alright alright alright 4.56 it is than.
what parts do I need to order?
and speaking about my leaking differntial, what would you guys do on the front axle? I just dont want to put any money in that garbage oem piece if im going to change it soon anyway.
thx again!
Click to expand...
HP30 out of a 99' or older XJ.
 
if your front differential is only leaking, I don't see a reason for swapping out your entire front axle to cure it unless you already have access to a HP30 donor.

When you regear, that is the perfect time for new seals on everything since you will be replacing the pinion anyway and you will have the axles, carrier etc out of the vehicle.
 
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Christoph0315 said:
alright alright alright 4.56 it is than.
what parts do I need to order?
and speaking about my leaking differntial, what would you guys do on the front axle? I just dont want to put any money in that garbage oem piece if im going to change it soon anyway.
thx again!
Click to expand...
Information for context: I've only had my TJ for a few weeks. It came with 33's and 4.56 gearing. I have never driven any other TJ with any other combination of tires and gears. I live in southeastern virginia where it is pretty flat....

With that being said, I love the combo. The 4.56 gears feel pretty good getting around town and through the few dirt roads I've taken it down.
 
WallyWest said:
LoL

Great post, A++, would read again.
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I'm hoping one day all my posts are condensed into one volume and sold in bookstores.

If you guys want to get a laugh , read "Letters from a Nut".

Jerry Seinfeld seems to be the one behind it. It is hysterical.
 
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