4.10 Re-gearing - 2025

[Rene_05]

Hello from central Ohio, first ever post. 2005 Liberty Renegade

This is a great forum and I appreciate all of the knowledge that has been shared here. I know regearing has been discussed at length on here, but given that our Jeeps are getting up in years, I was hoping to get some input.

I have acquired all of the parts to have the front and rear differentials regeared/rebuilt. This includes the parts listed below. I thought finding the front Dana gears would be the hardest part, but now I can’t find a shop to do the work. Did I mess up getting all of the parts myself? The rear gears are the only thing I could see that I probably should have let a shop obtain, but I figured a shop wouldn’t do the work of researching and getting all of the parts. Hoping to see if it’s just me. One labor quote I did get was 2,500 plus and it was apparent that they didn’t want to do it.

Here is my parts list if it would be helpful to anyone in the future. This is speckled in a lot of different threads, but needed to get it all in one place for myself.

Part	Brand	Part Number	Notes
Front 4.10 Gears	Dana Spicer	84006-5	3.73 to 4.10
Front Master Service Kit	Yukon	YK D30-SUP-KJ
Front LSD	Eaton	912A585 - Detroit TrueTrac	Fits in Dana 30, Including Dana 30A
Front Gasket	N/A	N/A	Lube locker not available for Dana 30A
Front axle seals - at the CVs	Timken	Timken SL260031
Front Seal - center	Timken	Timken 3946
Front Gear Lube	TBD	TBD	80W-90 conventional per LSD
Rear 4.10 (4.11) Gears	Yukon	YG C8.25-411	Axle spline is 29, pinion is 27
Rear Master Service Kit	Yukon	YK C8.25-C
Rear LSD	Eaton	912A553 - Detroit TrueTrac	For Chrysler 8.25 with 29 spline axles
Rear Differential Cover	ARB	Diff Cover Chrysler 8.25In (750005)	May require approximately half quart more gear lube than stock
Rear Axle Seals	Timken	Timken 8835S Seal
Rear Gasket	Lube Locker	Chrysler 8.25 Diff Gasket
Rear Gear Lube	TBD	TBD	80W-90 conventional per LSD manual

Here is my friend, Rene:

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[KJowner]

You have been busy!

Jeep looks good, nice and solid.

 

[Gyro]

When I had mine done about 10 years ago,labour worked out to be about the same as the parts cost.


Gyro

 

[Rene_05]

When I had mine done about 10 years ago,labour worked out to be about the same as the parts cost.


Gyro

Thanks, that makes sense. Given what things cost today, I figured between 2 and 3K, about two days of labor cost. I can’t get anyone to happily take my money to do it is the problem. I wouldn’t trust the shop that gave me the estimate to work on my bicycle with how rude they were . Also noted that the front differential would need to be completely pulled out to do it, which I don’t know if that is accurate.

 

[Rene_05]

You have been busy!

Jeep looks good, nice and solid.

Thanks! I’ve tried to take care of it over the years. I have done a lot to it myself, but regearing is out of my league.

 

[wheeee32]

Thanks, that makes sense. Given what things cost today, I figured between 2 and 3K, about two days of labor cost. I can’t get anyone to happily take my money to do it is the problem. I wouldn’t trust the shop that gave me the estimate to work on my bicycle with how rude they were . Also noted that the front differential would need to be completely pulled out to do it, which I don’t know if that is accurate.

Front diff definitely has to come out to swap the new gears in. It will feel like a new vehicle once you regear. Mine felt stronger and smoother when I accelerated. Fuel economy went back to stock numbers as well.

 

[duderz7]

It's not too bad to do yourself if you have time and patience. You might have to pay a shop to remove old and press on new bearings on the pinion and carrier as they are some special tools. And get a big breaker bar for the rear pinion. I picked up a 4 foot one. The required torque is somewhere around 500lbs. It cost me less to buy tools and take my time than paying anyone else for theirs.

 

[u2slow]

Consider saving the shop a step and take the front diff out yourself. If they are unfamiliar with the KJ, the loose part on the bench will show it's a fairly simple unit.

 

[Rene_05]

Consider saving the shop a step and take the front diff out yourself. If they are unfamiliar with the KJ, the loose part on the bench will show it's a fairly simple unit.

Thanks for the replies, I may look into at least pulling the diff out myself. I’ve had the whole front tore apart in the past for the lift, control arms, CVs, tie rods and wheel hubs, doesn’t seem like much more to pull the diff. To duderz7’s point, I usually prefer the ‘buy the tools and learn how to do it’ method. The precision required and cost of the parts inside is what makes me nervous.

If I have the front rebuilt off the truck and reinstall it, could I then drive it a short distance to a shop to have the rear done? (Or is stuff gonna blow up with the gear ratio difference)

 

[u2slow]

As long as you stay in 2wd, it won't matter what the ratios are.

I had the diff out for a whole summer, and had a 2wd-only KJ for the duration.

 

[Rene_05]

As long as you stay in 2wd, it won't matter what the ratios are.

I had the diff out for a whole summer, and had a 2wd-only KJ for the duration.

This is why this forum is great, thank you. This might be the way to reduce labor cost, still learn from the experience and also find a shop that will do the inner rebuilding . Assuming the torque settings for everything holding in the front can be done with a normal torque wrench, I should be able to do this.

 

[Rene_05]

Sharing a few good threads with tips on removal of the front diff:
https://www.jeepkj.com/threads/front-differential-removal.55782/post-629817

https://www.jeepkj.com/threads/remove-front-diff-without-removing-control-arms.81267/