question's about re-gearing

[hrjaw]

I was thinking about getting the wrangler re-geared and wanted to get every one’s thoughts and suggestions. It is a 97 TJ with 4.0 and three speed auto, 30 front and 35 rear with 3.07’s. Right now I have an ome 2.5 lift with 31’s tires. Adding armor, a roof rack, and a winch at some point. I “may” go to 32’s. maybe. I am trying to keep a good balance of daily driving and expo rig, not a rock krawler or monster rig. I was thinking of going to 4.11’s for gearing but also wanted to know what else I should consider. Oh yea, and she has 160,000 miles on her.

 

[ExpoMike]

Typically 4.10's are swapped in when you go with 31" tires but that is also with a 4 speed auto (the ones with OD). This keeps you close to stock gearing when running stock size tires.

For your setup having a 3 speed auto, I would not want to go that deep. When I put mine into 3rd gear, the RPM's at 65mph are almost 3000rpms. I would think in your combo, 3.73 gears would be as high as I would go but that is assuming you are not going bigger then 31's. 32's would be borderline and too low for 33's.

Not having OD really makes it hard to find that right balance between good freeway drivability and offroad crawling. Good luck. :coffeedrink:

 

[robert j. yates]

I'm running 4:56 withthe 3 speed auto and 35's. Its not an issue.

What the OP needs to do is decide if he is going to 32's or not. If he is then re-gearing would be beneficial but then there is the 35 to think of.

Personally, if you are going to spend money to re-gear that axle and run 32's then IMO, you need to look into kits that strengthen the axle.......or else carry spare shafts, c-clips and spider gears and know how to swap them in. Dana 35's tend to go boom once you start leveraging them into bigger tires and more weight.

 

[hrjaw]

let's assume i stick with the 31's. going bigger at this point will only be for the "look" factor and nothing else.

 

[Fergie]

let's assume i stick with the 31's. going bigger at this point will only be for the "look" factor and nothing else.

Another bit of info:

The 4.0L is happy running at 2600-3200 RPMs all day long. If you can live with it, then the engine can.

 

[hrjaw]

Another bit of info:

The 4.0L is happy running at 2600-3200 RPMs all day long. If you can live with it, then the engine can.

so you think re-gearing is not an issue then.

 

[SunDvl]

I am currently running 3.73's with 4.0L/3 spd/33's, as such I really need to make the jump to 4.10's. But living in flat land, it isn't killing me. I ran 3.73's (b/c they were stock in our Jeep) with 31's for a long time and had no complaints. IMO, you should make the jump to 3.73's, as the 3.07's are to high for offroad use or highway driving.

 

[Fergie]

so you think re-gearing is not an issue then.

Well, what do you want to attain through re-gearing?

Specifically.

Top cruising speed, low end acceleration, slow crawling ability?

 

[hrjaw]

i assume with all the extra gear (sliders, skids, rack, weight of two people plus dog and gear, etc) I am going to loose power. what I would like to do is compensate for the extra weight that is going to be on the vehicle. right now it is 75 % highway, 25 % off-road. with that in mind, i was hoping that the re-gearing will give me some power back. let's be honest, this thing is not made for acceleration and I drive like my Uncle Joe (slow and steady). if i could also get a few mpg's back, that would be great too.

 

[kjp98TJ]

agree with robert and others to the non-issue of rpm. i'm running 4.88's and 33x10.5's right now, although a 5 spd. pushing 200k miles on orig motor/tranny and clutch.

personally, i'd scour some jeep boards and look for some swapped out 4cyl TJ axles(4.10) for sale.

 

[ExpoMike]

My recommendation for the 3.73 came from the idea that mpg was somewhat important. The engine running at 3200-3400rpm is not a problem but it hits more in the pocket at these rpms then if you can get it closer to 2500rpm.

YMMV (pun intended) :hehe:

 

[IXNAYXJ]

Find a pair of axles out of a Cherokee (HP D30/ChryCo 8.25) in 3.73 and you'd be waaay ahead of where you are now. It would probably cost about the same as regearing, AND you'd have better axles. If you search right, you could even find a 29-spline 8.25 and a LS. Then you'd be cooking with gas!

-----Matt-----

 

[hrjaw]

Find a pair of axles out of a Cherokee (HP D30/ChryCo 8.25) in 3.73 and you'd be waaay ahead of where you are now. It would probably cost about the same as regearing, AND you'd have better axles. If you search right, you could even find a 29-spline 8.25 and a LS. Then you'd be cooking with gas!

-----Matt-----

please tell me more about this Matt

 

[Fergie]

Find a pair of axles out of a Cherokee (HP D30/ChryCo 8.25) in 3.73 and you'd be waaay ahead of where you are now. It would probably cost about the same as regearing, AND you'd have better axles. If you search right, you could even find a 29-spline 8.25 and a LS. Then you'd be cooking with gas!

-----Matt-----

You'll be able to find a front in 3.73, maybe, but def not a Chryco 8.25", at least not a factory version, and from my old research, there arent 3.73s available.

Also take into consideration that the rear axle would need TJ bracketry welded on, adding to cost and time.

Your other option is a Ford 8.8. You'd get factory 4.10s, disc brakes, but a much larger housing to drag around.

You can also swap in a 2wd Toy axle of certain flavors.

You can also get Rubi axles, or even a regular TJ Dana 44 with 3.73s and corresponding front axle.

Again, it all depends on your budget, and need.

Back to regearing, I'd say go for 4.10s, but def swap your axle out.

 

[IXNAYXJ]

You'll be able to find a front in 3.73, maybe, but def not a Chryco 8.25", at least not a factory version, and from my old research, there arent 3.73s available.

Yes, I'm sorry, I was thinking 3.55. Still an improvement both in gears and in axle strength for a small cost, and probably just fine for 32's.

The other option Fergie mentioned makes a lot of sense, too. If you can find a Ford 8.8 in 4.10 you get 31-spline shafts and disc brakes, then just find a cheap HP D30 and match the gears.

I guess the big question is your budget. One option is about $400 and range to well over a $1000.

-----Matt-----