? on 4.10 gears in the front

jctoth · **Posted:** Mon Jul 18, 2005 8:13 am

I just installed 265/75R16 tires on my lifted KJ and it has lost some pep. I would like to install 4.10 gears to regain some of it. I know DC is the only source for the gears for the Dana 30A in the front. For those that have done the swap is there anything special I need to know about the Dana 30A? Is the longer pinion shaft and aluminum housing the only differences between the Dana 30 and 30A? Any info would be helpful. Thank you.

LimitedLurker · **Joined:** Fri Jul 08, 2005 7:18 pm **Posts:** 114

As I understand it this is not just a gear swap. You actually have to get the diff that is setup with 4.10s and swap it with your current diff.

jctoth · **Posted:** Tue Jul 19, 2005 1:10 pm

I am confused. In our tech section we have two articles on how to install a Tru Trac diff in the front axle of the KJ. This would lead me to believe that the D30A uses the same carrier as a standard D30. Yet some claim that when installing 4.10 gears in the front of KJ that the carrier must also changed? If this is true does this means the Tru Trac (and other standard D30 diffs) only work in the front with gear sets other than 4.10 ratio? Someone please help!

InCommando · **Posted:** Tue Jul 19, 2005 2:40 pm

IF the gear break (3.55-down/3.73-up) for the carriers is the same as the regular D30, than the 4.10 and 3.73 use the same carrier. As the gears themnselves are different (thicker?) they may not be the same. But I wonder if it was not just cheaper/easier to get a complete 4.10 front, usually found under 4cyl KJ's, from ajunk yard to swap in than to buy the gears new from DC and pay to swap them? I know I'd try a whole front swap, but I lack the correct tools to set-up gears, especially on a daily driver.

AmericanMetal · **Posted:** Tue Jul 19, 2005 3:24 pm

Acually that's what I've been told to do. Just swap the whole unit out from a 4 cyl. Makes the most sense.

Grape · **Posted:** Tue Jul 19, 2005 5:13 pm

I believe my 05 3.7l 6speed has 4.10 gears. Does this seem right

PitViper · **Posted:** Wed Jul 20, 2005 6:33 pm

yes
on jeeps web site it shows 4.10 gears on the 05' sport, so if you have a sport then you probably do have 4.10.

I think that is good news really.... I just wish it was on the renny.

SethX9 · **Posted:** Wed Jul 20, 2005 10:41 pm

I went through this on the previous board. Apparently that 4.10 listing for the Sport on the Jeep site is wrong (I know, I know!) . The best way to make sure is to bend down and look at your diff for yourself.

InCommando · **Posted:** Thu Jul 21, 2005 12:07 pm

'05 V6 KJ's with the 6spd all have a 3.55 gear ratio. The website is wrong on several things. Only 4-cyl KJ's had the 4.10's. The standard is 3.73. The lower first gear in the NSG370 6-speed makes up for the higher gear ratio.

ltwgs · **Posted:** Thu Jul 21, 2005 2:47 pm

Some folks relate the 4.10 to what they call a 4.09. Are these compatible?

Grape · **Posted:** Thu Jul 21, 2005 3:50 pm

I was wrong i looked again at the sticker and it says 3.55

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

The D30 and the D30a have very similar ring and pinion gears, but they are not interchangeable. The 4.10 gears from a dealership will not work with the carrier for the 3.73's either. We replaced the entire front diff in mine with one from a 4 cylinder to get the 4.10's up front. It was cheaper than buying all the parts from the dealership, that didn't really know what all would be needed. 4.09's and 4.11's can actually be used with 4.10's. They are so close it won't cause a problem. You can get the Yukon 4.10 gears for the 8.25 in the rear from Randy's ring and pinion. That is what Rocky Road sells. They still have reverse D30 gears listed for the front and they absolutely will not work. They've known this for months and still haven't taken them off their website.

jctoth · **Posted:** Thu Jul 21, 2005 8:46 pm

What should be the going price for a front axle assembly from a salvage yard?

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

My mechanic found mine for $550 and had it in one day while my Jeep was on the lift. None of the 4 sets of gears that were sent would fit. The rear gears, and torque converter were already done. You might also look at the Dana 44a from a new Grand Cherokee. I've heard that Randy's makes 4.10 and 4.56 gears for them now.

? on 4.10 gears in the front

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