Who has 4.88s or 5.13s w/33s and auto?

colgatefootball · 05-06-2012, 02:15 PM

Hi,
I have a 2005 Rubicon with 33s (285s) and the auto tranny. It runs like a dog when I get to mountains and lugs too much around town and highway for my liking when I need to pass. On here and on pirate 4x4 there seem to be guys who know their stuff and say I need 5.13 gears, or 4.88 the least for the auto tranny in the '05s, and that power, mpg and tranny life will all improve.

This summer I think I can finally afford to regear and get it over and done with. Anyone else with 33s and the later TJ auto tranny running 4.88 or 5.13 with 33s? For now I keep the OD button off around town and on the highway for the most part. But if Im planning some runs to Big Bear, Utah, and Colorado, I need to regear this thing or I might go nuts. haha

Funny I thought getting the Rubicon saved me money by coming with 4.10 and lockers from the factory, figured 4.10s would be good for 33s or even 35s! Doesnt seem like it though driving this thing! I think the 6 speed would be a better choice than the auto if someone is looking at TJ Rubis now.

Any input or advice appreciated big time.

Thanks

**Jerry Bransford** · 05-06-2012, 02:46 PM

4.88 would be ideal for 33" tires and your 4-speed 42RLE automatic. 5.13 or 5.38 is ideal for 35" tires with that transmission.

**Unlimited04** · 05-06-2012, 02:53 PM

I have 4.88s with 33s. works good.

colgatefootball · 05-06-2012, 03:10 PM

Thanks both of you for your immediate responses!! Appreciate it big time...

Just sent an email to my mechanic to get pricing on getting it done....once I can swing that, then I can move on to getting the axleshafts rebuilt on my 98 4runner and maybe an ARB bumper for that thing(since I got in accident in my Rubicon recently and demolished a car but the Hanson bumper totally protected my Jeep and didnt even take paint off, made me think I want a bumper on anything I drive that isnt flimsy stock!)...then both of my toys will be ready for the woods this summer!

**MayRoll** · 05-06-2012, 07:02 PM

I wouldn't hesitate to gear 5.13 for 33's when talking 42RLE. 35" rubber needs at least 5.38. Unless you want to replace the carrier and dump the factory lockers, then 5.13 is as low as you can go.

You'll enjoy 5.13 gears and 33's. And get by with 35's.

popeyesides · 05-06-2012, 09:15 PM

Quote:

Originally Posted by MayRoll

I wouldn't hesitate to gear 5.13 for 33's when talking 42RLE. 35" rubber needs at least 5.38. Unless you want to replace the carrier and dump the factory lockers, then 5.13 is as low as you can go.

You'll enjoy 5.13 gears and 33's. And get by with 35's.

^^^ X2, been there done that, 5.13's and 33's are awesome, getting ready to put 5.38's and ARB's for my 35's to get the same gearing. You will never touch your OD button again. DO IT.

colgatefootball · 05-07-2012, 12:58 AM

thanks guys....so you have 5.13s with 33s or you did before moving to 35s? HOw did it do gas mileage wise? Not that I expect a lifted TJ with steel bumpers and skids, winch, etc, to get good mpg! Just wondering if its screaming around town or on the highway with 5.13s or its good to go....

Love the feedback from everyone!

**1tufrubicon** · 05-07-2012, 01:58 AM

Quote:

Originally Posted by colgatefootball

thanks guys....so you have 5.13s with 33s or you did before moving to 35s? HOw did it do gas mileage wise? Not that I expect a lifted TJ with steel bumpers and skids, winch, etc, to get good mpg! Just wondering if its screaming around town or on the highway with 5.13s or its good to go....

Love the feedback from everyone!

I have a twin to yours (05 Rubi, some armor, skids, winch etc and 33's. I have been running 5.13's for 4 years now and love it. One thing to be aware of though, with our 4.1 transfer case and 5.13's, the crawl ratio is pretty darn low. So low in fact that I've been on some down hill, shelf trails out in Death Valley where I find myself running out of braking power. The gearing overdrives the Jeep's ability to stop. I gotten off the trail with sweaty palms more than once! I'm talking three-point turn switch backs where you don't dare go over2 mph and most of the time all you can see is the sky before you fall 1000 feet down.

colgatefootball · 05-07-2012, 02:33 AM

wow thats intense!!!! Thanks for the input....looks like 5.13 might be it..

colgatefootball · 05-07-2012, 09:58 PM

those of you with 5.13 and 33s, what was the kinds of driving you did with the Jeep other than off road? Around town, any highway time, etc? Or just mostly wheeling? I have to drive 2-3 hours if not more for most trails, so I still want to be alright on the highway...but not putting up big hills or unable to pass! Or feeling like Im burning my tranny up like I do now if its single lane mountain road and I get stuck behind someone going at the wrong speed and my tranny is gear hunting and bogging...

**MayRoll** · 05-07-2012, 10:28 PM

Quote:

Originally Posted by colgatefootball

those of you with 5.13 and 33s, what was the kinds of driving you did with the Jeep other than off road? Around town, any highway time, etc? Or just mostly wheeling? I have to drive 2-3 hours if not more for most trails, so I still want to be alright on the highway...but not putting up big hills or unable to pass! Or feeling like Im burning my tranny up like I do now if its single lane mountain road and I get stuck behind someone going at the wrong speed and my tranny is gear hunting and bogging...

Gear hunting and 42RLE go hand in hand. It's .69 OD is a goofy ratio for the anemic 4.0L. Having experience with 33's and 35's with 5.13 gears, I'll tell you that you'll be zippy around town with 33's and 5.13's. And will reduce excessive gear hunting on long grades and hwy passing. And you'll love the crawl ratio in 4:1.

ijp4fun · 05-07-2012, 10:36 PM

FYI...Some people with 5.13's and 33s have experienced drive line vibrations they find nearly impossible to get rid of. The driveline is spinning pretty quick with this tire/gear ratio combination.

colgatefootball · 05-07-2012, 11:46 PM

Id love to feel zippy around town and be able to cruise up grades on highway! I dont want any vibes though, that would stink throwing money at gears and then have to chase driveline gremlins, been there and done that with too many of my Jeeps/trucks....

So if I wanted to waiver on side of caution Id go 4.88 it seems....

**SKINUM** · 05-08-2012, 05:19 AM

I'd go with 5.13's as well. I have the 42RLE and 35's (on a LJ) and although it works i'd like to have 5.38's. So, I'd go 5.13's for 33's.......

danb303 · 05-08-2012, 08:18 AM

Here is a good rule of thumb...

For each 1 inch increase in tire size you need to add 25 - 30 numbers in gears to keep the same gearing.
So, let's say you have 31' tires from the factory and go to a 35" tires (adding 4" of tire) then you need to add 100-120 numbers to your gears. If factory was 410 then you need at least a 513 to keep the facory gearing.

Keep in mind that you are going to have some loss of power feel due to larger tires....