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Learn to regear, upgrade axles, or sell?

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Some Random Guy

Some Random Guy

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Northridge 4x4 in the area should be able to figure this out. Last I heard the lead time for an appointment was way out there. 39's on D44 doesn't seem reasonable. Can you go back to 35's while saving for proper axles?
Yes, I can. Or I can just upgrade. That’s part of what I was trying to sort out when I started this thread.
My gut says I should be breaking teeth or twisting shafts if the 44 can’t handle a 73 pound tire, not blowing pinion bearings. And definitely not while being babied on a regear break-in. Ball joints were a pre-existing condition.

So I can afford to upgrade now, but I don’t want to spend $10k just because of 2 pinion bearings. I have competing demands for those funds. I’d want more evidence related to my useage than “because the internet said the D44 can’t” without explaining why. Early on people said it couldn’t handle bigger tires before they understood the JL D44 wasn’t the JK D44. If someone can help me connect the dots from tires to pinion bearing failure, that would help me make the jump now.
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OllieChristopher

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I would go with option three and do it yourself if there are no time constraints. If you know how to read and comprehend a service manual then it's a super easy job if you are patient and double check all your work.

It is labor intensive and takes patience. With mostly basic hand tools and a good set of feelers it's an easy weekend job for a first timer.

Only special tools for a full axle rebuild will be bearing puller/press. Setting pinion depth will be time consuming if you have not done it before. Just make sure you have plenty of shims on hand.

Backlash for a ring and pinion can be very subjective depending on application. .010" is a good baseline and safe for a street driven rig that sees some rock crawling or drag strip . For a hard core dedicated race rig I have seen as little as .005". A good rule of thumb is tighter means less chance of broken gears but accelerated ring/pinion wear. Loose means gears last longer with greater chance of breakage with heavy foot.



One tool that will be invaluable and save your hands is a brass drift punch.
 

mushroomax

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I vote for doing it yourself, there's plenty of information on this website for you to end up with a satisfactory result. And it's always good to have a second set of eyes to check your work and what better place than here to do that. That's also the number one reason why I posted a build thread; to ask questions, bounce off ideas with the masses, double check my work, and seek input.
 

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Hi,

Sucks you have had so much go wrong.

If you can read a dial indicator you can setup gears.

1st thing to note the pinion depth is usually setup by the factory so if you remove the shims on the factory pinion from that axle assembly and put it or same thickness on your new pinion, next start setting the new ring gear/carrier/locker in and shim it until you get the correct backlash measurement, and then verify the gear pattern, and that should be good.

I have seen front IFS differentials burn up bearing because of design and lack of oil, my 96 Tacoma I can't drive with the hubs engaged at highway speeds, the second time I overfill it and still don't use over 45mph

Good luck with the decisions, but new skills are something you will never regret.

Regards
Jim
 

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Lots of folks are running 40’s on the 44’s and they aren’t taking it easy on the rig, if built right these can be viable but it means trussing the rear and chromoly shafts and yeah gearing it. No you can’t rock hop and go beserk on the gas pedal but these will live.

You can’t regear a JL like a JK, the specs are different and no one is going to buy a rig with a broken rear diff your only option is to fix it if you are going to sell it.

While you are fixing it have the gears crypto treated and rem ISF polished, for a couple hundred more you can significantly strengthen the gear set, look it up.

Your other option is to call these guys

https://fusion4x4.com/collections/j...-semi-float-60-rear-axle-assembly-for-jeep-jl

For around 6k you can do what I did and buy a 40 spline semifloat 60, yeah yeah bent flange blah blah as long as your rig doesn’t weigh 7500 lb and you don’t jump it should be fine but for a couple grand more you can do a full float 60 and run wheel adaptors to address the bolt pattern to keep your 5 lug wheels.
 
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Ironically, the dealer offered me enough to recover everything I’ve spent except the labor for gear installs. They didn’t know about the issue because they caught me cold while I was there for something else. Offer was over $62k. I bought it for about $50k OTD and am about $10k into it for parts.
I’m going with another shop, down the street from me with a lot more experience on JL’s. If it goes South, I’ll do them myself. The guide videos posted here were very confidence building and the tool investment is lower than I thought. If I hadn’t already scheduled with the shop down the street, I’d probably have just redone this myself.
 

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...

Option #4, Wait for stock MOPAR 4.88's to become available to order. I'm guessing this will be around $6k to do front and back. This is way cheaper than 1-ton upgrades, but leaves me waiting. I can do the work myself, and it's MOPAR parts so I might have more luck with future dealers on warranty claims. Who knows how long it will be though. I might even recover half that by selling my front axle, and could potentially teach myself gearing on the broken rear one.
...

Has anyone got some better solutions, or some critiques of these options to improve them? Sorry for the ranting, it's been a rough week with my rig.
"Mopar" axles have been available for years with 4.88 gearing.

ULTIMATE DANA 4 4™ ADVANTEK® AXLE
P/ N 7 7072528 $4,399.00 (front)

RING AND PINION GEARS, DANA M210, 4.88 RATIO
Ring and Pinion Gears help maintain vehicle performance after
larger tires are fitted. Jeep® Performance Parts gears are made
from heat-treated 8620 steel. Gear ratio is 4.88:1.
P/ N 7 7072409 $395.00
Axle, Wide-Front.

P/ N 7 7072406 $2,295.00
Jeep® Wrangler Rubicon® Axle Assembly, Rear. (4.10 gearing)
2018–2021, Jeep® Wrangler JL
 

JeepFiend

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Sounds like you got it figured out, so that's good.

But just my $0.02, I have had multiple Currie axles in my Jeeps previously, 9" in my Yj, 9" and D44 in my XJ. Both times it did require new driveshafts, but aside from that, they were direct bolt in assemblies with the small exception that the 9" went from drum to disk brakes, but even that was pretty straightforward.
 
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Forgot to mention, this would allow me to order a 2 door and eliminate my monthly payment, I could afford it outright. More budget for broken things after that.
But I’m going to get the 4 door fixed and keep wheeling it until my car gets here. Maybe then I’ll consider the trade just to eliminate the car loan.
 

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My gut says I should be breaking teeth or twisting shafts if the 44 can’t handle a 73 pound tire, not blowing pinion bearings.
Too much torque breaks the driveline components. Torque is RXF. It's the 37" lever that's creating too much torque. The weight of the vehicle (of which the tire weight increase is negligible) and the traction from the tire with a long lever (tall tires) breaks components.
 
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Original shop test drove and scoped the vehicle today. They say it's just a loud gearset, no bearing issues. To their credit they recommended trying a new manufacturer, because more Yukon gears will be machined from the same batch, the same way, and likely lead to the same result in my diff.
My third shop called BS and called Yukon's sales manager who was pretty upset, but the return call confirmed to stay away from Yukon for my particular rig.
Too much torque breaks the driveline components. Torque is RXF. It's the 37" lever that's creating too much torque. The weight of the vehicle (of which the tire weight increase is negligible) and the traction from the tire with a long lever (tall tires) breaks components.
I do understand how torque works, I threw in the weight to demonstrate there are those with heavier tires on a smaller size presenting similar challenges that don't have issues. It's about the equivalent of an 82 lb tire at 35" or a 77 lb tire at 37". FYSA, it's not a 39" lever, it's a 19.5" lever (less under load, more like 18.5-19") because you're dealing with radius, not diameter. A 35" tire would be a 17.5" lever. I know there's more to it then that (moment of rotational inertia actually determines the "length of the lever", weight of the vehicle means more traction with a bigger contact patch that allows more torque to build up before slip when on level ground, trigonometry leads to higher torque on the gearset when on non-level ground, etc), but again I had a setup go bad during break-in street driving, not wheeling. This is why I don't buy into the axles can/can't handle certain sizes end of story argument in my particular case. I'll be the first to admit on these forums if I start twisting things up on the trail that the D44 can't handle my particular setup and offroad driving style. I've planned for that and have reserve funds for a 1-ton upgrade if that happens, but I'd rather let them make returns if it isn't needed.
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