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  Topic Review (Newest First)
01-04-2020 10:55 PM
sprkeng
Quote:
Originally Posted by ronjenx View Post
Quote:
Originally Posted by sprkeng View Post
My Jeep was built on 05-28-10 stamped with a Dana 30 3.21 front and Dana 44 3.73 rear.

[IMG class=inlineimg]/forum/images/JeepForum_2016/smilies/tango_face_smile.png[/IMG]
It sounds like you are saying your JK has 3.21 in the front and 3.73 in the back. If that were so, you would not be able to drive in 4wd.


Do the same check for the front axle and you will see it has the same ratio as the rear.
I got the Chrysler Jeep factory build sheet emailed to me yesterday for my '11 JK. And it's confirmed that the Dana 30 and Dana 44 has a 3.73 gear ratio OEM out of the factory.

Gears are for sure confirmed.

I'm still going to add regearing up to 4.53 ratio onto my bucket build list. I figure a budget of $6000 regear front and new axel for rear installed

I already replaced the OEM lift with 2.5" installed cost me $1300

Bought new Bestop Trektop $800 installed with window storage bag.

More Build List items to do:

New (5) 35" tires and wheels $2500

Front and rear bumpers replace OEM plastic with New steel with winch
$3000 ?

New hood painted $2800

Leather seat covers $500

New sound system with GPS $2500

Will I be better off buying a new Jeep? LOL
12-30-2019 06:56 PM
sprkeng
Quote:
Originally Posted by ronjenx View Post
Quote:
Originally Posted by sprkeng View Post
My Jeep was built on 05-28-10 stamped with a Dana 30 3.21 front and Dana 44 3.73 rear.



[IMG class=inlineimg]/forum/images/JeepForum_2016/smilies/tango_face_smile.png[/IMG]
It sounds like you are saying your JK has 3.21 in the front and 3.73 in the back. If that were so, you would not be able to drive in 4wd.


Do the same check for the front axle and you will see it has the same ratio as the rear.
You bring up a good point. I'll have to take a second look at my front axle, my rear is definitely a D44-3.73, it's on the dealer original equipment list, but that list doesn't specify the front axle other than it's a D30. I guess I'll have to lift the front and check the rotation to see what it comes up to. "scratch my head"

Thanks.
12-29-2019 06:27 PM
ronjenx
Quote:
Originally Posted by sprkeng View Post
My Jeep was built on 05-28-10 stamped with a Dana 30 3.21 front and Dana 44 3.73 rear.



It sounds like you are saying your JK has 3.21 in the front and 3.73 in the back. If that were so, you would not be able to drive in 4wd.


Do the same check for the front axle and you will see it has the same ratio as the rear.
12-29-2019 05:39 PM
sprkeng
Quote:
Originally Posted by MilitaryJK4455 View Post
Thanks ronjenx, for writing this out for us.

Finding Your Gear Ratio

Here is a procedure to get the axle ratio when it is not known. Build sheets (available from your dealer, or from the Jeep web site) will only tell you what the Jeep had from the factory. A used Jeep could have been re-geared.

If you want to know for sure, and remove all doubt, do this:

Chock the front tires, fore and aft.
Put the transmission in neutral.
Emergency brake off.
Jack the left rear tire off the ground.
Put a jack stand under the frame, just in case the jack fails (had to add this).
Put an index mark on the aft end of the drive shaft, visible from the left rear wheel.
Put an index mark on the left rear tire at the 6 o'clock position.
Rotate the left rear tire 2 complete revolutions while counting how many times the index mark on the drive shaft passes its original position.
That number will be your axle ratio.
Remove jack stand and lower jack.
Put transmission in gear or Park, apply emergency brake.
Remove chocks.
If you have limited slip, jack up both rear wheels and rotate one revolution, making sure both tires rotate equally.

If the drive shaft rotated almost 3 1/4 turns, you have 3.21
If the drive shaft rotated almost 3 3/4 turns, you have 3.73
If the drive shaft rotated a little over 4 turns, you have 4.10
If the drive shaft rotated a little under 5 turns, you have 4.88
If the drive shaft rotated a little over 5 turns, you have 5.13

Now go drink a beer and feel confident that you know your gear ratio without a doubt

This is very informative. Simple and to the point.

I purchased my 2011 JK Sport 2-door standard in 2012. I fortunately had the part number sticker on the front axle and the steel tag on the rear axle. My Jeep was built on 05-28-10 stamped with a Dana 30 3.21 front and Dana 44 3.73 rear.

I found this thread last night, so this morning I decided for giggles to try it out.

I counted just under 4 turns for the rear axle, so it does work.

02-20-2015 08:37 PM
1222
Quote:
Originally Posted by SlickJeeper View Post
i need help are 5:13 gears good for a 2010 wrangler on 35's or is that to low of a gear ratio?
5.13ís are the most popular gear choice for the JK with 35ís and auto. Some people go as low, high numerical, to 5.38ís and are very happy with that choice also. This is all for the 3.8 engine (2007-2011) which you have. For those that have the 3.6 (2012-2015) this does not apply.

It would help if you would fill in your profile so we can give better advice. For instance, we have no idea what transmission you have which will reflect just what gears to select.
02-20-2015 07:41 PM
Maertz Na id do 5.38
02-20-2015 07:22 PM
SlickJeeper i need help are 5:13 gears good for a 2010 wrangler on 35's or is that to low of a gear ratio?
06-04-2014 05:20 PM
1222
Quote:
Originally Posted by jwmbishop View Post
Raised one rear tire, rotated 2 times, got dizzy and fell down. Drank another beer, raised another tire (on the front this time), rotated two times (this time remembering to turn the TIRE duh), but the muffler didn't turn so lost track or what I was doing.
Drank another beer.
Drove to mechanic to show me how to do the simple check - forgetting to take jacks out. Thank the lord for steel jack wheels - rubber would not have lasted 6 miles.

Does this mean I have a CAI instead of a gear ratio?
No it means you should stick to iced tea instead.
06-04-2014 01:59 PM
jwmbishop Raised one rear tire, rotated 2 times, got dizzy and fell down. Drank another beer, raised another tire (on the front this time), rotated two times (this time remembering to turn the TIRE duh), but the muffler didn't turn so lost track or what I was doing.
Drank another beer.
Drove to mechanic to show me how to do the simple check - forgetting to take jacks out. Thank the lord for steel jack wheels - rubber would not have lasted 6 miles.

Does this mean I have a CAI instead of a gear ratio?
06-03-2014 08:57 AM
ronjenx
Quote:
Originally Posted by Airborne Lee View Post
Raised Jeep, turned wheel two times, had six beers, I must have 3.10 gears?
See what you get with just one beer.

Did your drive shaft turn a little less than 3 and 1/4 turns?
06-03-2014 08:27 AM
Airborne Lee Raised Jeep, turned wheel two times, had six beers, I must have 3.10 gears?
06-01-2014 05:28 PM
ronjenx Here is the condensed version:

Jack one front tire off the ground.
Put a chalk mark on the tire and the drive shaft.
Rotate the tire by hand 2 complete revolutions while counting the drive shaft turns. The number will be your gear ratio.
A little less than 3 and 1/4 turns will be 3.21 gears.
About 3 and 3/4 turns will be 3.73 gears.
A little over 4 turns will be 4.10 gears.
06-01-2014 05:19 PM
cheroxy
Quote:
Originally Posted by cheroxy View Post
Sorry to resurrect this old thread, but I did what it said on my 2003 TJ and got 7.25 rotations on drive shaft to the 2 rotations of my tire. I have 35" tires on 15" rims. Are these numbers for JK's only?
Nevermind, a little more digging found it, I had both tires rotating instead of just one. It looks like i Have the 3.73 stock ratio.
06-01-2014 05:11 PM
cheroxy Sorry to resurrect this old thread, but I did what it said on my 2003 TJ and got 7.25 rotations on drive shaft to the 2 rotations of my tire. I have 35" tires on 15" rims. Are these numbers for JK's only?
11-29-2012 10:48 PM
riot1987 It out of a mid 70's 1/2 ton chevy
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