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ialex2005i 05-01-2006 07:57 AM

Need to gear!
I have a 2001 4 cyl. I have 31" super swampers ltb's (kinda wish I would have gotten tires that do better on the road) But my jeep struggles to get to 55!!! I've done some research and found that I need to regear.. I know absolutely nothing about this:

What should my gearing be?
Where do I get these gears?
Where can I get this done?
Is it hard for me to do?

-newbie to jeeps! :D

Brice 05-01-2006 09:51 AM

i am not sure on what gear you should get with a 4cl. i am getting mine done right now and i am going with 3.73 but i have a v8 and 33in tires there are charts on line to help you with that. i got my gears and everything else i needed from i called there tec line and they were helpful and free shipping. as far as doing it yourself i dont know i went to the shop that was doing it for me and looked at what they were doing and saw that i am glad that i am not doing it. looked like a job that i didnt need to do

Jerry Bransford 05-01-2006 01:08 PM

To regear means to replace the ring & pinion gears inside your axles, both the front and rear. R&P gears are available from any 4x4 shop who does regearing, and most do. They require true expertise to install and the job is time consuming to get right. If they're not installed correctly, the new gears will be quickly ruined which is why this a job best left to experts.

Plan on around $1200 plus or minus a hundred bucks or so. This includes parts and labor to regear both axles. Don't make the mistake of buying cheaper gears online to give to the installing shop either because if anything goes wrong, you'll have the gear installer pointing fingers at the gears and the gear manufacturer pointing fingers at the installer. Having the installing shop provide the gears means they are responsible for everything in case something goes wrong, and it happens... it happened to me once after a fresh R&P installation.

Your TJ most likely has 4.11 gearing and your two choices are to go to 4.56 or 4.88. Those who have gone to 4.88 have been real happy with their regained performance with tire sizes up to 33". For the $1200 cost, it's not worth it to only go from 4.11 to 4.56 as that's a very minor change. That's why I suggest 4.88.

HOWEVER, you are reporting poor performance with even 31" tires so you may be one of the rare individuals with 3.73 gearing in your axles and not the more common 4.11 gearing found in TJs with the 2.5L engine.

The proper ratio really depends on two things... what kind of transmission you have, automatic or manual transmission, and what is the maximum size tire you will ever install on your TJ.

So first, which transmission do you have? And second, what is the max tire size you'll ever install?

ialex2005i 05-01-2006 01:58 PM

thanks for the replies.. I have an automatic, and the max tire size I will do is 33" .. which I hope comes soon cause these ltb's scare the crap out of me on the highway.. But I'll deal with them until they lose their tread.. 4.88 sounds good.. the more power the better.. I don't want to go 4.56 if I won't feel much of a difference.. It's definently annoying when you're on a road in which the speed limit is 65 and I can only get my jeep to 55 and the pedal is against the floor.. :(

Jerry Bransford 05-01-2006 02:07 PM

Look on your axle's differential cover where you'll find a small tag bolted between two bolts on the left-hand side of the cover. Your axle's ratio will be embossed into it, though take a flashlight and a rag with you since it's hard to read and it's likely covered with dirt.

It'll either have 4.11 (or 4.10 depending on which axle you look at) or 3.73 (or 3.74 again depending on which axle) embossed into it.

This is just to double-check what you have now.

With your 3-speed automatic, it's quite possible you have a 3.73 and not a 4.11 ratio. At any event, 4.88 is too low for the 3-speed automatic like you have. I'd go no lower than 4.56 (and 4.88 is a lower ratio than 4.56 is) for 33" tires as you don't want your engine RPMs too high. :)

ialex2005i 05-01-2006 03:08 PM

I haven't been able to look at my gearing yet on the case (at work).. But could I just buy an air locker with 4.56 gearing? Or do I need to still regear.. as I said, I know nothing about this.. If I plan to buy a locker later on, would this be the smarter way of going about it.. Or does this not change my gearing set up?

sound hound 05-01-2006 05:08 PM

A locker just ties your'e left and right tires (axles) together in the differential case, which is where your'e ring and pinion (gears) reside. If you are considering both, locker(s) and re-gearing it may be cheaper to get it all done at once. Let the shop open it up, have at it one time, and be done.

ialex2005i 05-03-2006 04:40 PM

okay, so I looked under my lovely but wimpy jeep.. and I'm running a 3.73 gearing.. so should I go to 4.56?? :D

Jerry Bransford 05-03-2006 08:20 PM


Originally Posted by ialex2005i
okay, so I looked under my lovely but wimpy jeep.. and I'm running a 3.73 gearing.. so should I go to 4.56?? :D

4.56 if you plan to stick with 31/32" tires, 4.88 if you think you might end up with 33" tires.

ialex2005i 05-03-2006 08:33 PM

I plan on making this thing pretty hefty one day.. so I think I'll go with 4.88.. Thankyou for the help.. and great website you have :D hope I can do all that one day.. (minus the broken axel) :D

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