4.10 gear question

Mutt · **Posted:** Thu Apr 20, 2006 2:55 pm

Perusing the site, I've learned that the only 4.10 gear set that will work in the front diff is the one out of the four cylinder KJ due to it being a D30A and not a run of the mill 30.

My confusion starts when I noticed that posters were stating that you had to replace the carrier also? My thinking is that a certain diameter ring gear is the same as a ring gear of the same diameter, someone please enlighten me? I've also seen what appeared as posters saying they had replaced the entire third member..........was this really necessary?

I'm also interested in Eddo's front diff reinforcement collar. There was some discussion about locating a collar that didn't need to be machined to the proper inside diameter, but I never saw what the outcome was.

This whole IFS (Inferior Front Suspension) thing is new to me. Just trying to transform the Liberty into a capable and reliable trail rig to take the whole family wheeling in.

the1jferg · **Posted:** Thu Apr 20, 2006 10:36 pm

The KJ DANA's are funny. I can't speak for the front end but I can tell you my rear Dana 35 has a diff (larger) size "RG" than any other Dana 35 out there (ever made) and a cover with different bolt pattern than any other dana 35 ever made, and my tone ring is on the ring gear.

I can only get 4:10 ratio from a 4cyl KJ with Dana 35. I would like to do this but need to find out if they can change that setting in the COM-Puter

Something on the 30a might be diff: "These improvements include
an all-aluminum carrier and tube for improved fuel efficiency, larger pinion
stem and bearings for enhanced NVH characteristics, and net-formed
differential gears for increased strength and durability."

http://www.prnewswire.com/cgi-bin/stori ... 140&EDATE=

http://dana.mediaroom.com/index.php/press_releases/1685

Maybe they should "net form" the carrier :lol:

fmc1 · **Joined:** Mon Jul 18, 2005 10:34 am **Posts:** 19

The carrier break for all Dana 30’s is 3.55 and down, 3.73 and up. So if you are going from 3.73 gears to 4.10 you DO NOT need a new carrier.
The reason that sometimes the carriers change is to compensate for changes in ring gear thickness do to changes in the diameter of the pinion gear. The diameter of the ring rear does not change.

I don’t see why replacing the third member is necessary since the Dana 30 has no third member. Third member type differentials they are fairly rare I can only think of four types off the top of my head, the Toyota 8”, Dodge 8.75 and the Ford nine inch.

Replacing the entire front axle assembly with one from a 4 banger should work fine. The axle housings are exactly the same. However the half shafts from the 4 banger have different part numbers than the V6, I don’t know what the difference is if anything. So to be on the safe side you might want to also buy the half shafts from the donor vehicle in case the V6 half shafts don’t work

The speedometer in the KJ is driven from the ring gear speed so if you change gear ratios you DO NOT need to neither correct the speedometer nor make any computer changes.

Guest · **Posted:** Fri Apr 21, 2006 12:34 pm

fmc1 wrote:

The carrier break for all Dana 30’s is 3.55 and down, 3.73 and up. So if you are going from 3.73 gears to 4.10 you DO NOT need a new carrier.
The reason that sometimes the carriers change is to compensate for changes in ring gear thickness do to changes in the diameter of the pinion gear. The diameter of the ring rear does not change.

I don’t see why replacing the third member is necessary since the Dana 30 has no third member. Third member type differentials they are fairly rare I can only think of four types off the top of my head, the Toyota 8”, Dodge 8.75 and the Ford nine inch.

Ford 8" and Isuzu 12 bolt, too. I think mitsu has one as well...

Mutt · **Posted:** Fri Apr 21, 2006 12:39 pm

You pretty much confirmed what I thought.

Sorry, for using the misnomer "Third member" when I was referring to the entire housing. It was more of a lack of a better term.

I sure love the 9" Ford pumpkin for ease of setup. It's nice being able to carry into the garage and work on the bench. I've seen pics of the D30A totally removed and on a bench also though.

I'm hoping that I can pick up a four cylinder 4.10 gear set only for a fraction of the cost of an entire assembly. Now to locate a wrecked four banger.

Thanks for the input.

chefdab · **Posted:** Fri Apr 21, 2006 1:33 pm

I don't think you have to replace the axle half shafts. JeepinAl put the 4:10 in his before he started fabbing the 5" lift and I don't recall him saying he had to replace the axle shafts.

Jeepin Al · **Posted:** Fri Apr 21, 2006 1:49 pm

I put the 4.10 gears in, no problem! No carrier change etc, etc. You do need to buy the front gears from the dealer, howver. It was an easy swap.

Al

ChileanKJ · **Posted:** Fri Apr 21, 2006 4:10 pm

If i'm correct the front and the rear must have the same ratio so my 2004 CRD have 4.10 Rear and front from the factory.

Claudio

Jeepin Al · **Posted:** Fri Apr 21, 2006 9:42 pm

Yes the front and rear gear ratio must be the same. You could have 4.1 and 4.11 however. They can not be 3.9 and 4.1. It is recommended not to put a full time locker in front, such as a detriot locker of power trax. Limited slip and air lockers are out. I would use a limited slip such as the true trac.

Al

jnc91 · **Joined:** Mon Jul 11, 2005 3:52 pm **Posts:** 32

fmc1 wrote:

The carrier break for all Dana 30’s is 3.55 and down, 3.73 and up. So if you are going from 3.73 gears to 4.10 you DO NOT need a new carrier.
The reason that sometimes the carriers change is to compensate for changes in ring gear thickness do to changes in the diameter of the pinion gear. The diameter of the ring rear does not change.

I don’t see why replacing the third member is necessary since the Dana 30 has no third member. Third member type differentials they are fairly rare I can only think of four types off the top of my head, the Toyota 8”, Dodge 8.75 and the Ford nine inch.

Replacing the entire front axle assembly with one from a 4 banger should work fine. The axle housings are exactly the same. However the half shafts from the 4 banger have different part numbers than the V6, I don’t know what the difference is if anything. So to be on the safe side you might want to also buy the half shafts from the donor vehicle in case the V6 half shafts don’t work

The speedometer in the KJ is driven from the ring gear speed so if you change gear ratios you DO NOT need to neither correct the speedometer nor make any computer changes.

I take it from this post that if you have a 5-speed with the 3.73 gears you can change to a 4.11 rear end. Is this correct?
Jeff

KY Liberty · **Joined:** Sat Jul 09, 2005 1:46 pm **Posts:** 1195

If you have 4 wheel drive, you need matching gears like Jeepin Al said. If you only have 2 wheel drive, you can actually put 4.56's in the rear. It's not about the transmission. It's so the transfer case or differentials won't tear themselves apart. The easiest way to get the 4.10's up front is to pull the front diff out of a 4 cylinder with low miles.

tazer · **Joined:** Wed May 03, 2006 3:35 am **Posts:** 28

OK I just might be wrong here and to be sure I will check my paper work when I get home but I am almost certain that the liberty sport came with the 4.10 gears from the factory in 04 even with the 3.7 engine. It was only the limited and the renagade that came with 3.73's. If I am wrong please tell me.

Jeepin Al · **Posted:** Wed May 03, 2006 7:37 am

Take a look at the band around the rear axel, it is a sticker from the factory and it should be there unless the dealer took it off. It has the gear ratio and diff type printed on it. To be really sure the vin number codes (i think) and /or build sheet (which I haven't found yet, thats if Jeep even hided them in the Liberty) should have the code for the 4.10 gears. Someone posted a while back that you can get an electronic copy of the build sheet on the Jeep website. I have never tried it, however.

Mutt · **Posted:** Wed May 03, 2006 9:26 am

Jeepin Al wrote:

Take a look at the band around the rear axel, it is a sticker from the factory and it should be there unless the dealer took it off. It has the gear ratio and diff type printed on it.

Yep, did that. My '04 Sport is a 3.73 one legger.

Guyute1210 · **Posted:** Wed May 03, 2006 1:17 pm

Jeepin Al wrote:

To be really sure the vin number codes (i think) and /or build sheet (which I haven't found yet, thats if Jeep even hided them in the Liberty) should have the code for the 4.10 gears. Someone posted a while back that you can get an electronic copy of the build sheet on the Jeep website. I have never tried it, however.

I dont believe there is a vin code for the gears. You can get a build sheet from the Jeep website.

Jeepjeepster · **Posted:** Wed May 03, 2006 4:31 pm

All libbys come with 3:73 unless its a four banger.

Is ChileanKJ right about the CRD's coming with 4:10 from the factory? Never heard of this?

Edwin · **Posted:** Wed May 03, 2006 7:26 pm

tazer wrote:

OK I just might be wrong here and to be sure I will check my paper work when I get home but I am almost certain that the liberty sport came with the 4.10 gears from the factory in 04 even with the 3.7 engine. It was only the limited and the renagade that came with 3.73's. If I am wrong please tell me.

When I went to the Jeep website in '04 and "built my Jeep", they listed it with 4.10's. But, they come with 3.73's, unless it is a 4 cylinder. I guess it was a misprint.

CRDSTU · **Posted:** Mon May 08, 2006 6:54 am

When I worked for Jeep here in Australia, all of our 2.5lt Manual CRD KJ's came with 4.10 gears. About 2 years later, we had a batch of 2.5lt 4 cyl MANUAL PETROL KJ's come out - these also had 4.10 gears. Hence why I am looking for a wrecked one to pinch the gears out of myself

!! I've got an 05 built CRD LTD AUTO & want the 4.10 gears - mine came with 3.73's....

tazer · **Joined:** Wed May 03, 2006 3:35 am **Posts:** 28

Edwin wrote:

tazer wrote:

OK I just might be wrong here and to be sure I will check my paper work when I get home but I am almost certain that the liberty sport came with the 4.10 gears from the factory in 04 even with the 3.7 engine. It was only the limited and the renagade that came with 3.73's. If I am wrong please tell me.

When I went to the Jeep website in '04 and "built my Jeep", they listed it with 4.10's. But, they come with 3.73's, unless it is a 4 cylinder. I guess it was a misprint.

Yep you are so right. That is what I remember now. Thanks for setting me straight. I need that sometimes.

4.10 gear question

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