35's with Auto tranny and 5.13 gears?

**bfewkwa** · 08-26-2009, 10:36 PM

I just bought my 04 Rubi last weekend and have been trying to figure out what all the previous owner had installed. I was originally told that the Rubi still had the original 4.10 gears in it. When driving home from CO I would often have to kick the OD off to keep from lugging the engine.

Today, I heard back from Scott at Mike's Offroad in Boazman, MT (who did the modifications) and found out that my Rubi was regeared with Yukon 4.88 gears and that it has upgraded Tom Woods driveshafts.

I'm now wondering if I wouldn't be happier with 5.13 gears. Can anyone who is running 5.13s with 35's and an auto give me some feedback?

I do a lot of highway driving at the moment and I'm turning about 2200 RPM at 70mph. That is right on the edge of lugging the motor down when I start coming up a high.

Would running 5.13s place the motor in a sweeter spot in the powerband?

**Unlimited04** · 08-26-2009, 10:53 PM

5.13s would be ideal for 35s with the 42RLE auto. i think you'll be fine with 4.88s since you already have them tho.

i turn 2000rpms at 70mph, on 3.73s and 31s...so you're 200rpms more...which seems pretty good to me if you do a lot of highway driving. you won't be winning any races tho.

Emagg · 08-26-2009, 10:59 PM

i have 4.56 gears 35 and auto trans on a 2000 jeep wrangler (no overdrive ) i tach 3100 at 70 MPH if you do a lot of highway driving i think 5.13 gears would be to big but you need someone with an overdrive trans to answer better hope this helps.

saddis · 08-26-2009, 11:04 PM

Quote:

Originally Posted by Unlimited04

5.13s would be ideal for 35s with the 42RLE auto. i think you'll be fine with 4.88s since you already have them tho.

i turn 2000rpms at 70mph, on 3.73s and 31s...so you're 200rpms more...which seems pretty good to me if you do a lot of highway driving. you won't be winning any races tho.

X2 plus you would be spending a lot of money to go from 4.88's to 5.13's which is only one gear size depper. IMO it would'nt benifit enough to make up for dropping that amount of cash.

**Bennettj13** · 08-26-2009, 11:11 PM

I'm planning on doing 5.13's with 35's on the 42RLE as well. I'm wondering what my top speed will end up being, or if it will even be possible to keep highway speeds anymore. It's going to happen anyways, but I'm hoping I can still keep up on the way to the trail. lol

uvalax236 · 08-26-2009, 11:15 PM

I have 5.13's and 35's. LOVE THE SETUP! The axles are even set up (in gearing) to go to 37's if I wanted. Better than stock performance IMHO.

**bfewkwa** · 08-26-2009, 11:23 PM

Quote:

Originally Posted by uvalax236

I have 5.13's and 35's. LOVE THE SETUP! The axles are even set up (in gearing) to go to 37's if I wanted. Better than stock performance IMHO.

What kind of RPMs are you turning at 70 mph? Are you still having to kick overdrive off pulling up a long hill?

**Bennettj13** · 08-26-2009, 11:28 PM

Quote:

Originally Posted by uvalax236

I have 5.13's and 35's. LOVE THE SETUP! The axles are even set up (in gearing) to go to 37's if I wanted. Better than stock performance IMHO.

How is the highway driving? The RPMs manageable? What's your top safe speed?

ZIMM18 · 08-26-2009, 11:44 PM

i would like to hear how this plays out, going to install my 35's in two weeks and I'm a 05 rubi with stock gears and 42rle auto as well. i hear this 5.13 is the hot lick setup becuase we have the overdrive. please keep us posted. also heard there is a thick ring gear and regular ring gear. suppose-of-ly the rubi has thick ring gear from what i remember seeing on this forum or maybe that was for switching to ARB lockers...........

**planman** · 08-26-2009, 11:47 PM

At 70 mph, with 35s and 5.13s on an 04 automatic would put you at 2380 rpms.

The 4.88s would put you at 2264 rpms (you posted you are at about 2200 rpms), and 4.10s would put you at 1902 rpms.

The 5.13s will probably give you that extra horsepower by running at almost 120+ more rpms at 70 mph. It shouldn't cost you more than about $1000 to regear.

If you can sell your used 4.88s for a couple hundred $ or more, it might be worth it if you live/drive at a higher elevation in CO.

Your top speed will still be faster than you should really drive a TJ.

**Bennettj13** · 08-27-2009, 12:28 AM

Sweet. Thanks.

**Sccafire** · 08-27-2009, 12:54 AM

Quote:

Originally Posted by bfewkwa

I do a lot of highway driving at the moment and I'm turning about 2200 RPM at 70mph. That is right on the edge of lugging the motor down when I start coming up a high.

Here is my 2 cents worth. I just had 5.13 installed about 2 months ago on a stock Rubicon (w/35s) gearing. At 65mph I am turning 2200rpm with OD on. I am still getting used to the new gears and how it drives with the new gears. At first I did not like it. The more I drive the Jeep the more I like it.

When I was doing research on what gears to get I was told that 4.88 are better if you do alot of driving and 5.13 are better offroad. I went to 5.13 due to the Jeep is not a DD.

**mudb8** · 08-27-2009, 01:43 AM

5.13's are the best gear even for 33's with the 42rle auto tranny.

2200 at 65 is nothing, plus if there's any grades the 4.88's don't cut the mustard... at least it's not good enough for me.

**bfewkwa** · 08-27-2009, 05:59 AM

Thanks for the feedback. Sounds like 5.13 is the way to go for me to be happy with the driveability.

**RedRubiconLJ** · 08-27-2009, 06:35 AM

Ive run 513's since June 06 and love them. I had 35's initially but went to 37's.