I need re-gearing advice!

[cj5guy]

I have a 2011 JK Unlimited Rubicon.  Currently running 35's on 17" rims with a 4" MOPAR lift.  Lost of other weight added to it: bumpers, skids, etc.  It's an AUTOMATIC and runs 90% of it's time in Northern VA traffic/highways, with as much trail riding as I can squeeze in.  My question is:

4:88 or 5:13???     I've yet to get warm fuzzies over which one makes the most sense for me.  I hear I might be running too high an RPM with the 5:13, but then I hear just the opposite.  One day - WAY DOWN THE ROAD, I might go to 37" tires but no plans to do so anytime soon . . . well, maybe.  I welcome advice and experiences.  Also, part of the re-gearing is going to include the Superior Axle & Gear Ring & Pinion Overhaul Kit.

And please - don't say I shoulda waited for the 2012 . . . it's too late now.   

[(Tattoo) Jack]

    Well... there are lots of Gear Ratio Calculators/Formula's online so you can figure out which gears you want based on the road speed/RPM's you want. Here's my 4 cents...

    First, while you're driving at your normal highway speeds (the ones you travel the most) down shift till you find the RPM that's desirable. Mark it down, now you need to figure out what your actual ground speed is, then you should be able to figure out (using the formulas you found online with ACTUAL, measured, tire height) to calculate what gear ratio you will need to replicate the desired RPM/Speed.

    My Opinion: IF you're gonna spend the money to replace the R&P, the Case and... where most of the $$ goes to, LABOR, then you should give it some serious thought into installing Traction Devices. The Case is probably gonna cost ya $100 or more so you can deduct that off the cost of the T.D. I know, it's a big investment, BUT if you don't do it now and decide to do it later you're gonna spend all the money for Labor all over again. Paying twice for the same service plus tossing the Case. Just some food for thought...

   Good Luck, Tatt

 

[monk3ytoes]

I know it's not a JK, but my (4cyl) 2.5L yj is regeared to 4.88 and it pushes 35s.  It'll accelerate hard but it won't go over 60-65 unless it's downhill.

Personally, I think 35s are big enough for anything offroad.  I think you'd be good with 4.88s.

[hillbilly]

the higher gears push easier, but your top end speed suffers. i went with 488 over 456 and my top speed is 60-65, 91 xj 6.5 lift and 33 - 35's.
just my fyi.

[j.haffly]

the higher gears push easier, but your top end speed suffers. i went with 488 over 456 and my top speed is 60-65, 91 xj 6.5 lift and 33 - 35's.
just my fyi.

I know it's not a JK, but my (4cyl) 2.5L yj is regeared to 4.88 and it pushes 35s.  It'll accelerate hard but it won't go over 60-65 unless it's downhill.

Personally, I think 35s are big enough for anything offroad.  I think you'd be good with 4.88s.

This thread is the one I was looking for!  I'm planning on 4.88's...running 33's right now in my 2.5L TJ with 4.11's....highway driving with any type of hill, let's just say it's "fun"..NOT

Next question....I take it I will need to change the cases for 4.88's....if so, does one need to change the axles as well....

Also planning on at least a locker in the front....should I consider a complete axle swap that is "just" bolt on and be done with it instead of just piece by piece?

Jim

[Rick_Bear]

Jim,

The gear set will slide right in your present carriers when purchased for the correct year axle housing.

Look at spending $800 to $1,200 per axle for a gear swap unless you can do it yourself.
The gear purchase is cheap compaired to the labor for someone else to do it.

[j.haffly]

Jim,

The gear set will slide right in your present carriers when purchased for the correct year axle housing.

Look at spending $800 to $1,200 per axle for a gear swap unless you can do it yourself.
The gear purchase is cheap compaired to the labor for someone else to do it.

wow....that much....didnt realize the labor for that was that high....

[Jeremy]

I finally swapped out the 2.73 R&P in my 1981 CJ8 for 4.11s  (and you thought your gearing was bad!)  It is a smidgen to low a gear for 31" tires if I were to run  highway speeds a lot,  just about right for 33" tires. My bill was $2200 but included installing a lock right locker (which I had) and one piece axle shafts in the rear.  This was expensive for my budget but I really wish I had done this SOOOoooo much sooner. 

[j.haffly]

Jim,

The gear set will slide right in your present carriers when purchased for the correct year axle housing.

Look at spending $800 to $1,200 per axle for a gear swap unless you can do it yourself.
The gear purchase is cheap compaired to the labor for someone else to do it.

yea, I just got told from a shop here right around $1,000 per axle....is it that hard?  Honestly?  I mean crap, me and two other folks did the lift....

If someone up there is able to help me or talk me through it, as I've never done a gear change before.... I'm more than willing to provide pizza, beer, soda, illegal Cuban cigars...ok, maybe not on the Cuban cigars but you get my drift....

[j.haffly]

I did find a place in Loundon county that will do it for $600, front and rear out the door, I bring the gears....

[Jeremy]

With gearing,  there seems to be a bell curve on cost verse experience.  What I have found is shops that do gear swaps a lot tend to have the specialty tools and the experience to do a good job relatively quickly and painlessly.   A shop that does NOT do a lot of gear swaps may muddle through the job but it will take time and there for cost more as they may not have some of the specialty tools or experience and there for have to do a LOT of trial and error before the gears are set up properly.  More time equals more cost.  When looking at shops one of the first things I would do is ask how many ring and pinions swaps they do on a regular basis. 

[j.haffly]

that makes sense...the place that was recommended to me in Purceville, VA specializes in Jeeps from what their website says....but I might have to do this in two stages....an axle at a time with the knowledge that I cant use 4wd till both are done....I mean, $300 per axle plus parts....cant beat it from what I'm seeing!

Jim

With gearing,  there seems to be a bell curve on cost verse experience.  What I have found is shops that do gear swaps a lot tend to have the specialty tools and the experience to do a good job relatively quickly and painlessly.   A shop that does NOT do a lot of gear swaps may muddle through the job but it will take time and there for cost more as they may not have some of the specialty tools or experience and there for have to do a LOT of trial and error before the gears are set up properly.  More time equals more cost.  When looking at shops one of the first things I would do is ask how many ring and pinions swaps they do on a regular basis. 

[(Tattoo) Jack]

    Just remove the front DS so there won't be any accidents.

   While its apart, u might as well have them install new seals.

   Jack

[CJ8Ted]

I always thought the low price shops were giving the customer a break in price for the "experience" and so you don't yell as loud if you have to come back in.

For an older axle.
New seals, bearings, lube, gasket (if needed), pinion nuts, crush collar (if needed) and the gears will set you back 400 to 500 for the parts alone. Don't skimp on any of the above if you want it to last.

As for doing the job yourself,,, Read the web on installs, if you do not understand what in going on don't try it. The ring and pinion have some of the closest tolorances of any part of a car or truck. If you understand and have the tools than go for it.


Ted

[j.haffly]

I always thought the low price shops were giving the customer a break in price for the "experience" and so you don't yell as loud if you have to come back in.

For an older axle.
New seals, bearings, lube, gasket (if needed), pinion nuts, crush collar (if needed) and the gears will set you back 400 to 500 for the parts alone. Don't skimp on any of the above if you want it to last.

As for doing the job yourself,,, Read the web on installs, if you do not understand what in going on don't try it. The ring and pinion have some of the closest tolorances of any part of a car or truck. If you understand and have the tools than go for it.


Ted

Yea, I will be buying the master rebuild kit for each axle as well....but I wont be doing it myself...one, dont have the tools, two, have never done anything even close to this....I understand what is going on but having not done it or even watched it being done, I'll pass....I think I'll have the rear done first and have them remove the front DS at that time....as Jack suggested....

Jim