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Best re-gear option?
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=104&t=89267
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Author:  motionsik [ Fri Sep 21, 2018 1:28 am ]
Post subject:  Best re-gear option?

Hey guys, new to the forum blah blah blah.

I'm doing a ton of work on my 2011 kk and putting about $10,000 into it to make it a spectacle that's fit for some light to moderate off-roading.
To the point; I am installing a 3 inch lift and some larger tires (Yokohama Geolander MT 265/70/17) I know that they will fit just fine but id like to know what re-gear would be recommended, how much on average it would cost and what some quality parts for the re-gaer would be.

Any advice for a new KK modder?

Thanks a bunch!!

Author:  lfhoward [ Fri Sep 21, 2018 7:28 am ]
Post subject:  Re: Best re-gear option?

Hello,
I’ve looked into regearing too, but my finances haven’t caught up with this idea yet! Anyhow, this is what I’ve found out.

265/70R17 is a 32” diameter tire (31.6). To get mostly back to stock performance, power, and gas mileage, you’d need 4.10 gears. (stock for a 29” tire is 3.73.) However; 4.56 might work better by providing a little extra oomph for towing and hill climbing. With a 31” tire I’d recommend a 4.10 ratio, and for 32” tire, 4.56. Yours being a 31.6” tire could go either way, but 4.56 might be more fun.

You’ll need the ring & pinion sets, master install kits, and a professional installer for each axle. For the front, you need a Dana 30 set for a JK Wrangler. (KJ liberties were different, so search for the JK.) You’ll want to get an OEM Dana Spicer gear set for the front. The rear is a Corporate 8.25, which is a pretty standard differential used on a lot of Chrysler products over the years. Yukon and Motive make good quality gears for the 8.25 IIRC. These may not be the least expensive out there, but cheap gear sets tend to develop a whine on the highway that will drive you nuts.

The gear sets aren’t cheap, but the labor is more. This is a time intensive job that must be done right and with precision. Install and parts can range from $1000-$1500 per axle depending on where you live and the cost of labor. You could do it yourself if you have specialized tools and experience, but screwing it up ruins the gear sets so I recommend shelling out for a reputable shop to do the work.

Author:  Ted15 [ Fri Sep 21, 2018 11:41 am ]
Post subject:  Re: Best re-gear option?

I can honestly say that those tires are too big. I had 31x10.5x15 and had enough problems that after they wore out I went back to 245/75-16. The front end also can’t handle the added stress. The geniuses at mopar put a heavy duty car front end in there. I’m on my third set of bearings and forth or fifth set of axles and these ones are blown out too. 2” is the max lift without putting RCV axles in. Also, be careful about the lift you choose. Spacers above the coilover are a bad idea because of the stress on the shock and spacers over the spring are worse. If you haven’t started buying parts yet, remember the old phrase “buy once, cry once” :JEEPIN:
4.10 gears are near perfect for 31” tires. It’s a good idea to lock those axles while they’re doing the gears too.

Author:  tommudd [ Sun Sep 23, 2018 4:28 pm ]
Post subject:  Re: Best re-gear option?

Like has been said before 4.56 for the size tire you are looking at is best
4 inches of lift as well and since its a KK, even more work to make it perform to the fullest
I run 265-70-16s ( 30.6 inch tall tire with 4.10s and its perfect for overall driving and pulling trailers
By the way I have over 150,000 miles experience with 4.10s in both 265-75-16s and 265-70-16s
Have also lifted over 55 Libertys so far and through various builds pretty much know what does and does not work or barely gets by
As far as lift ONLY JBA coilovers for going as high as you are wanting to , trust me ............


10,000 ? :shock: for just moderate off roading ?

Author:  tc1uscg [ Tue Oct 16, 2018 2:44 pm ]
Post subject:  Re: Best re-gear option?

Ted15 wrote:
I can honestly say that those tires are too big. I had 31x10.5x15 and had enough problems that after they wore out I went back to 245/75-16. The front end also can’t handle the added stress. The geniuses at mopar put a heavy duty car front end in there. I’m on my third set of bearings and forth or fifth set of axles and these ones are blown out too. 2” is the max lift without putting RCV axles in. Also, be careful about the lift you choose. Spacers above the coilover are a bad idea because of the stress on the shock and spacers over the spring are worse. If you haven’t started buying parts yet, remember the old phrase “buy once, cry once” :JEEPIN:
4.10 gears are near perfect for 31” tires. It’s a good idea to lock those axles while they’re doing the gears too.


Thats good to know. I've been running larger then stock for years (got my KK in 09 New). Currently running 255/70/16's, BFG All Terrain T/A KO2's since last summer. Replaced Goodyear Wranglers LT245/75/16's what were on stock rims. I replaced the rims when I went to the BFG's. Went to 8inch wide, zero offset. On a real tight flex, I get a little rub int he front. Rear rub also but I pretty much have to have a tire off the ground. Better in mud then any major "rock attack".

I never touched my axles. Since it was new, it's covered under the lifetime warranty and if when I was thinking of a limited slip for the rear, I decided against it. After some soul searching, decided to just make sure I have my winch if I wanted to do anything nasty. I do have the JeepingByAl 1.5 OME lift so that gives more wiggle room. But so far (knock on wood). I've not had any problems with the front end. The other then my poopy gas mileage, I have noticed that even on level ground, I don't have to hold the brake to keep it from moving forward. Runs the people behind me crazy :lol:

Author:  Ted15 [ Wed Oct 17, 2018 11:14 am ]
Post subject:  Re: Best re-gear option?

tc1uscg wrote:
Ted15 wrote:
I can honestly say that those tires are too big. I had 31x10.5x15 and had enough problems that after they wore out I went back to 245/75-16. The front end also can’t handle the added stress. The geniuses at mopar put a heavy duty car front end in there. I’m on my third set of bearings and forth or fifth set of axles and these ones are blown out too. 2” is the max lift without putting RCV axles in. Also, be careful about the lift you choose. Spacers above the coilover are a bad idea because of the stress on the shock and spacers over the spring are worse. If you haven’t started buying parts yet, remember the old phrase “buy once, cry once” :JEEPIN:
4.10 gears are near perfect for 31” tires. It’s a good idea to lock those axles while they’re doing the gears too.


Thats good to know. I've been running larger then stock for years (got my KK in 09 New). Currently running 255/70/16's, BFG All Terrain T/A KO2's since last summer. Replaced Goodyear Wranglers LT245/75/16's what were on stock rims. I replaced the rims when I went to the BFG's. Went to 8inch wide, zero offset. On a real tight flex, I get a little rub int he front. Rear rub also but I pretty much have to have a tire off the ground. Better in mud then any major "rock attack".

I never touched my axles. Since it was new, it's covered under the lifetime warranty and if when I was thinking of a limited slip for the rear, I decided against it. After some soul searching, decided to just make sure I have my winch if I wanted to do anything nasty. I do have the JeepingByAl 1.5 OME lift so that gives more wiggle room. But so far (knock on wood). I've not had any problems with the front end. The other then my poopy gas mileage, I have noticed that even on level ground, I don't have to hold the brake to keep it from moving forward. Runs the people behind me crazy :lol:


I was informed by the dealer that I never had a lifetime warranty on anything. Bought my 2010 new.

Author:  tc1uscg [ Wed Oct 17, 2018 6:41 pm ]
Post subject:  Re: Best re-gear option?

Not sure about 2010 models but 09 and maybe 08's had it. But only for the first owner but 2nd owner did not. Not even an option to carry it over.. Coworker has a 09 Rubi and she said thats the ONLY reason she wont get rid of it.i have used it for the front drive shaft, tension pully and water pump ans 2x on tranny pan. :pepper:

Author:  tommudd [ Wed Oct 17, 2018 6:53 pm ]
Post subject:  Re: Best re-gear option?

Warrantys are laughable anyways
My 04 I bought new with warranty, had complete new suspension, ARB bumper and many mods before it was 6 months old

Author:  tc1uscg [ Fri Jul 05, 2019 2:18 pm ]
Post subject:  Re: Best re-gear option?

tommudd wrote:
Warrantys are laughable anyways
My 04 I bought new with warranty, had complete new suspension, ARB bumper and many mods before it was 6 months old


Mine has saved me around $2k so far so I'm ok laughing at it... :mrgreen: :dizzy:

Author:  andrei vit [ Tue Nov 09, 2021 1:55 am ]
Post subject:  Re: Best re-gear option?

Hi, I read this thread on the forum and want to ask where I can get information on how to properly upgrade the axles on my 2011 Jeep Liberty/Cherokee KK diesel, front axle Dana 30 IFS 186 mm, rear axle corporate chrysler 8.25 " 210 mm, 3.21 mainframe

Author:  Homeward_Bound [ Sat Nov 13, 2021 10:52 am ]
Post subject:  Re: Best re-gear option?

andrei vit wrote:
Hi, I read this thread on the forum and want to ask where I can get information on how to properly upgrade the axles on my 2011 Jeep Liberty/Cherokee KK diesel, front axle Dana 30 IFS 186 mm, rear axle corporate chrysler 8.25 " 210 mm, 3.21 mainframe



We share the same front diff as the JK D30, so any JKD30 gears will work. Rear is the same from the KJ and WK so again, what fits there will fit the C8.25.

What size tires are you planning to use?

Author:  andrei vit [ Sat Nov 13, 2021 11:13 am ]
Post subject:  Re: Best re-gear option?

Homeward_Bound wrote:
andrei vit wrote:
Hi, I read this thread on the forum and want to ask where I can get information on how to properly upgrade the axles on my 2011 Jeep Liberty/Cherokee KK diesel, front axle Dana 30 IFS 186 mm, rear axle corporate chrysler 8.25 " 210 mm, 3.21 mainframe



We share the same front diff as the JK D30, so any JKD30 gears will work. Rear is the same from the KJ and WK so again, what fits there will fit the C8.25.

What size tires are you planning to use?



265/70/R17, 32"

Author:  Homeward_Bound [ Sun Nov 14, 2021 5:55 pm ]
Post subject:  Re: Best re-gear option?

andrei vit wrote:
Homeward_Bound wrote:
andrei vit wrote:
Hi, I read this thread on the forum and want to ask where I can get information on how to properly upgrade the axles on my 2011 Jeep Liberty/Cherokee KK diesel, front axle Dana 30 IFS 186 mm, rear axle corporate chrysler 8.25 " 210 mm, 3.21 mainframe



We share the same front diff as the JK D30, so any JKD30 gears will work. Rear is the same from the KJ and WK so again, what fits there will fit the C8.25.

What size tires are you planning to use?



265/70/R17, 32"


Having to dive a bit into the diesel specs since they came with a different transmission, I believe I found your answer.

Export diesel engines were mated to the W5A580. After finding the transmission ratios, I used the gear calculator found on [url]grimmjeeper.com/gears.html[/url]

Stock gearing 3.21Image

3.73Image

4.10Image

You will either want to go with 3.73 or 4.10. 3.73 will bring you back to near stock rpm on the engine. 4.10 will net more torque. Personally, I would go with 3.73.

Since the images are having a issue loading, the links below are for the album that has the chart I used as well as another link to grimmjeeper's ratio calculator.

https://m.imgur.com/a/2ndGE3i

Grimmjeeper.com/gears.html

Author:  andrei vit [ Mon Nov 15, 2021 12:17 am ]
Post subject:  Re: Best re-gear option?

Thanks for the complete information and the work done for me, I completely agree with this conclusion, the only thing left to decide what locks to put in the gearboxes of the main pairs, I am considering two options:
1.EATON Trutrac in both gears
or
2.EATON Trutrac in the front gears, Powertrax® No-Slip in the rear gears

What do you think about this?
Thanks.

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