Regearing from 3.73's to 4.10's

[blue_kjR417]

I've been giving serious thought to regearing my 05 Limited 4x4 with the 3.7 to 4.10's so that I can run bigger tires more comfortably. I've done as much searching as I can but to be honest it all seems very confusing to me. I can't keep up with the conversations within the threads nor weed out the irrelevant information. I did find this list for parts from JBA.

here is my shopping list so far (everything will be purchased from JBA to support an awesome company and keep it simple for future liberty owners):


(JEEPIN BY AL SKU - PRODUCT LINK)

D30KJ-410LIB-OE - Nirto Grear 4.10 Ring and Pinion
YK D30-SUP - Yukon Bearing & Seal Kit
C8.25-410-NG - Rear Diff Ring and Pinion 4.10
MKC 8.25-B - KJ - Master install Ring and Pinion rear diff.

If I purchase these parts and find a local specialist to do the change is there anything else I'm missing? Can someone who knows what there doing just install those parts with some of my existing equipment and make it all work? I saw in a few posts you have to flash the computer and that it could be done by a dealer or with a hypertech programmer, is that accurate? If there are most details to all of this please let me know.

 

[tommudd]

I've been giving serious thought to regearing my 05 Limited 4x4 with the 3.7 to 4.10's so that I can run bigger tires more comfortably. I've done as much searching as I can but to be honest it all seems very confusing to me. I can't keep up with the conversations within the threads nor weed out the irrelevant information. I did find this list for parts from JBA.



If I purchase these parts and find a local specialist to do the change is there anything else I'm missing? Can someone who knows what there doing just install those parts with some of my existing equipment and make it all work? I saw in a few posts you have to flash the computer and that it could be done by a dealer or with a hypertech programmer, is that accurate? If there are most details to all of this please let me know.

Pretty much it, when I went to 4.10s on mine it was pretty much put back to stock. We tried to get it a little closer doing the pinion reset but stock settings with 4.10s and 32s was pretty close . Now after a certain year don't think a pinion set can be done , can't remember what year right now though

 

[blue_kjR417]

Pretty much it, when I went to 4.10s on mine it was pretty much put back to stock. We tried to get it a little closer doing the pinion reset but stock settings with 4.10s and 32s was pretty close . Now after a certain year don't think a pinion set can be done , can't remember what year right now though

Forgive my ignorance tom, what do you mean by put back to stock and trying to get it a little closer? What is a pinion reset? Did you have to flash your computer? What technique did you use? Dealer or personal programmer?

 

[tommudd]

Forgive my ignorance tom, what do you mean by put back to stock and trying to get it a little closer? What is a pinion reset? Did you have to flash your computer? What technique did you use? Dealer or personal programmer?

I had the pinion rest after I went to a 30 inch tire,
After we did the gears ( Jeep Dealership Tech did the rears at the shop after hours) we started setting it and was pretty much back like it was stock settings
Dealerships have the computer programmer to do it
no on the personal programmer

 

[blue_kjR417]

I had the pinion rest after I went to a 30 inch tire,
After we did the gears ( Jeep Dealership Tech did the rears at the shop after hours) we started setting it and was pretty much back like it was stock settings
Dealerships have the computer programmer to do it
no on the personal programmer

Ok I gotcha, what if I found a set of factory 4.10 front and rears from a 4 cylinder model? Other than the sometimes difference in drive shaft yokes is there anything else to keep in mind that would prohibit them from bolting right in?

 

[tommudd]

Ok I gotcha, what if I found a set of factory 4.10 front and rears from a 4 cylinder model? Other than the sometimes difference in drive shaft yokes is there anything else to keep in mind that would prohibit them from bolting right in?

No not at all , done 3 swaps like that at my place for John and Two bobs on here and mine , ( well second time around on mine)
I never even have to bleed the brakes etc, pull the calipers/ e-cables etc for the rear
Front you have to cut two bolts that are in backwards to remove easily
But other wise pretty easy really
I paid less than 3 bills for the last 4.10s rear diff i got , low mileage one as well

 

[Jim McClain]

When you say re-gear to 4:10s, does that mean both front and rear differentials? May seem like a dumb question to some, but I'm pretty clueless about this and want to make sure I do it right, if I do it.

 

[John3seventeen]

Yes Jim that is correct. Both differentials must be regeared to match each other.

 

[dude1116]

Yes Jim that is correct. Both differentials must be regeared to match each other.

Unless you want to know what an exploding steel pumpkin sounds like

 

[tommudd]

Unless you want to know what an exploding steel pumpkin sounds like

I think the T-case right under their butts would be the first to go, ...wonder what that would be like..............mmmm I have an extra.....:whip:

 

[blue_kjR417]

Well correct me if I'm wrong but you can run opposing gear ratios front a rear, but not in 4wd. Probably be a good idea to remove the front drive shaft to ensure it didn't get engaged but for a short period of time moving between installs or something I think its ok as long as its never put in 4wd.

On another note, I have found a set of used axles from a 4 cylinder with 4.10 gears from a local salvage yard. Their prices were $395 for the front and $695 for the rear plus 8.5% sales tax with a 30 day warranty. They said they were removed from the vehicle at 76,000 miles. I haven't been able to find any other front axles, but I did find another used rear online for $447 free shipping, it has a 90 day warranty but does not disclose the actual mileage it just has 5 stars for mileage and condition. So I can get the local pair for $1182.65 or I can mix match with the local front and online rear for $875.58. Obviously the mix match is the best price especially in comparison to the new parts to install in my current axles from JBA which will be probably $900 after shipping plus $400 for a local install and I'm not sure what a dealer will charge to flash the computer. But I can't decide if its worth $300 more to know the exact mileage of the rear axle with a 30 day warranty vs. not knowing the mileage with a 90 day warranty. My current mileage is over 162K so its likely most of what I find from a salvage at this point will be better mileage than that, not guaranteed but likely. Any suggestions?

 

[u2slow]

On another note, I have found a set of used axles from a 4 cylinder with 4.10 gears from a local salvage yard. Their prices were $395 for the front and $695 for the rear plus 8.5% sales tax with a 30 day warranty. They said they were removed from the vehicle at 76,000 miles. I haven't been able to find any other front axles, but I did find another used rear online for $447 free shipping, it has a 90 day warranty but does not disclose the actual mileage it just has 5 stars for mileage and condition. So I can get the local pair for $1182.65 or I can mix match with the local front and online rear for $875.58. Obviously the mix match is the best price especially in comparison to the new parts to install in my current axles from JBA which will be probably $900 after shipping plus $400 for a local install and I'm not sure what a dealer will charge to flash the computer. But I can't decide if its worth $300 more to know the exact mileage of the rear axle with a 30 day warranty vs. not knowing the mileage with a 90 day warranty. My current mileage is over 162K so its likely most of what I find from a salvage at this point will be better mileage than that, not guaranteed but likely. Any suggestions?

The only 4.10 stuff I could find within travelling distance was a broken front (good internals) for $350. Nothing in 4.10 for the 8.25" rear.

OTOH, I can find complete 3.73 diffs so cheap and easy (private, CL, etc). Its almost worth getting spare diffs, install new 4.10s yourself, and swap the diffs on a long weekend.

 

[tommudd]

The only 4.10 stuff I could find within travelling distance was a broken front (good internals) for $350. Nothing in 4.10 for the 8.25" rear.

OTOH, I can find complete 3.73 diffs so cheap and easy (private, CL, etc). Its almost worth getting spare diffs, install new 4.10s yourself, and swap the diffs on a long weekend.

Short weekend, less than a day :icon_lol:

 

[u2slow]

Short weekend, less than a day :icon_lol:

^ Even more reason to go the spare diffs route