opdsgt

Vehicle: '08 2-door JK, 6-speed manual with 3" lift and 33" KM2s (quite heavy, near GVWR all the time with big driver, big bumpers, winch, tire carrier, Jerry cans, etc.; previously geared w/3:73s).

Well gang, after copious searching for a reputable gear man to install 4.88s in my Jeep's front and rear differentials, I found Ron just up the road from me. He's the owner and proprietor of R & S Unlimited.

Ron was extremely patient with me, fielding lots of questions before and after the work. His price for labor was exceedingly fair and I'm happy to report the gears are dead quiet and the Jeep runs great, as if it gained 40 horsepower.

Two days removed, I've done two heat cycles of driving followed by parking the JK and letting the gears fully cool. In short, I am 110 percent pleased with the 4.88s. Power everywhere (not Hemi power, but power nonetheless). It remains flexible though; lug it in 6th and still accelerate up hills or spin it in the lower gears for genuinely impressive passing power.

Results, GPS-verified (JK properly calibrated for 33s and gear ratio thanks to an AEV ProCal):

• 60 mph = 2,600 rpm
• 65 mph = 2,800 rpm
• 70 mph = 3,000 rpm
• 75 mph = 3,200 rpm

So, 75 is my new top cruising speed barring an emergency situation where I'm running from outlaw bikers on Harleys. Then I'll drive 80 to get away from 'em.

Seriously though, the motor doesn't feel taxed at 75. I wouldn't want to run a lot higher revs than that all the way across the state, but with a 5,500 rpm redline on the little V6, 3,200 rpm @ slab speed is nothing to get exercised about.

I basically drive it like a 5-speed now; 2nd is first, 3rd is second, so on and so forth. A nice byproduct of the new ratio is a fractionally higher than 4:1 crawl ratio in 1st gear low, tres kewl!

Thanks to David @ Northridge for continued excellent support of my mod habit and thank you to Ron @ R&S for outstanding and fairly priced work to get my Jeep back on the road.

hohokom

I recently did the same thing, and I have a 2008 6-speed as well. I am happy with the results, with the exception that when I pull a small trailer, it seems to take a considerable amount of time to get really moving, but this has changed since I went with the 35"s. When I was running the 32" M/T's, I seemed to have more power than I do now.
All in all, a good investment and happy with the results..

opdsgt

Yeah, I might have gone to 5.13s had I plans on running 35s, but I like the stance and off-road performance of the 33s, so the 4.88 seems to be a good fit.

bOLsAK=3

Thanks for the info!

Very helpful for those of us interested in a great future upgrade.

Robert

I'm glad to hear of your 4.88 success. I have an appt to do the same. Couple of questions from a newb if you don't mind. What locker did you use? What's an E-disco. Does it involve John Travolta

opdsgt

At the risk of answering a question(s) asked in jest, the rear locker is the factory optional electronic locker as comes standard on Rubicon Dana 44s. I have an open Dana 30 front and I opted not to put a locker in it. It does feature BLD (Brake Lock Differential) that helps some in poor front tire traction situations by applying brake to the side that loses traction, but it's not a true locker.

The e-discos ( ) are simply the factory optional electronic disconnecting front sway bar, again a Rubicon feature, bought when I ordered my Wrangler X through the dealership.

Overall, I'm very happy with the setup for a daily driver.

Robert

I should have read your post better. Rubicons came with all that didn't they. Thanks

Goranothos

I am also considering having this done. If you don't mind my asking, how much money am I looking at going from 3.21 to 4.56 or 4.88? I want it done right (not "on the cheap") and I only want to do it once.

Robert

I paid $2000.00 for the gears and the locker. I think the locker was about $650.00. That price was for Yukon gears.

Another shop quoted a price of $3000.00 + tax to go 4.10 or 4.11 (I can't remember which) using Mopar/Dana parts.

The cheaper shop also has a long reputaion in this area for Jeep Mods so it was an easy decision.

porters

Hows the MPGs now?