Yukon ring and pinion 500 mile break in?

[Joshin38]

I was just told when I dropped my rubicon off that I would need to put 500 non highway miles on my Jeep or it would void the warranty. Sounds like bullshit but want some feedback from you guys.

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[2Wheel-Lee]

I was just told when I dropped my rubicon off that I would need to put 500 non highway miles on my Jeep or it would void the warranty. Sounds like bullshit but want some feedback from you guys.

It's always recommended to always put 500 miles on a new gearset, then take it back for inspection and fresh fluid.
I just did my 500 mile inspection and fluid change this weekend.

What's odd is that people don't do this for new vehicles when they really should, I think.

 

[Oletimer]

I just did mine at 3500 and im glad i did. It looked pretty rough . However i had a pinion gear failure and a new ring and had it all replaced.
I took thermal readings today after 35 mile drive home. I put dino oil back in it , so i will check it tomorrow and see just for kicks the temps

 

[jlewissystem]

I got new gears and followed the break-in process to 500 miles. If you get new gears, that’s expected. Stock, I wouldn’t think that’s needed.

 

[2Wheel-Lee]

Stock, I wouldn’t think that’s needed.

Why not? What's the difference?

 

[jlewissystem]

Why not? What's the difference?

I don’t have tons of experience with this, but this would be my assumption:
Stock gears have pre-assembled spacing within the components. When you replace that hardware, the spacing needs to be recreated. As “tweaking may be needed”, I believe it’s best practice to follow that process so there isn’t any major wear damage, IF there needs to be any adjustment. Also, the replacement gears have markings on the teeth that wear off with friction, into the gear fluid. That fluid needs to be changed.

That’s my guess.

 

[2Wheel-Lee]

I don’t have tons of experience with this, but this would be my assumption:
Stock gears have pre-assembled spacing within the components. When you replace that hardware, the spacing needs to be recreated. As “tweaking may be needed”, I believe it’s best practice to follow that process so there isn’t any major wear damage, IF there needs to be any adjustment. Also, the replacement gears have markings on the teeth that wear off with friction, into the gear fluid. That fluid needs to be changed.

That’s my guess.

New replacement gears are the same as new gears that came in the Jeep...just a different ration. There are no markings on teeth on replacement gears that wear off. Replacement gears are setup nearly the same way as the factory. Specific specs should meet setup spec requirements at both the factory, and the regear. There is really no difference.

Is the stock gear "pre-assembled spacing" that you're referring to is the etching on the pinion indicating its depth? Replacement Spicer gears also have this etch. This only tells about how much pinion shim should be used. It tells no one anything about backlash and bearing preload, which all has to be setup - at the factory, or during a regear.

Seeing how my rear gear oil looked at 1800 miles along with the excessive backlash, it should have been inspected and adjusted earlier (though it was probably too late, as it was likely set up poorly at the factory).

 

[jlewissystem]

New replacement gears are the same as new gears that came in the Jeep...just a different ration. There are no markings on teeth on replacement gears that wear off. Replacement gears are setup nearly the same way as the factory. Specific specs should meet setup spec requirements at both the factory, and the regear. There is really no difference.

Is the stock gear "pre-assembled spacing" that you're referring to is the etching on the pinion indicating its depth? Replacement Spicer gears also have this etch. This only tells about how much pinion shim should be used. It tells no one anything about backlash and bearing preload, which all has to be setup - at the factory, or during a regear.

Seeing how my rear gear oil looked at 1800 miles along with the excessive backlash, it should have been inspected and adjusted earlier (though it was probably too late, as it was likely set up poorly at the factory).

Yeah, I was referring to that etching. Maybe it’s the same type of situation for new and replaced. I wouldn’t expect new oil to be “worn” that quickly, but maybe there’s something I haven’t seen with new JLs yet or your situation is unique. Others will have to chime in.

 

[Oletimer]

I should have stated i changed mine at 700 and now again at 3500. I think yukon gears maybe produce more wear in particles than dana gears which i used for years.

 

[twisty]

My shop said 500 miles for my yukons. For the front I recall 12 fwd runs in high and no more then 20 outings, then change it.

Make sure you use locktite on the front. The field is seeing the drain bolt come out when it takes hits on rocks or whatever. I had the shop give it a hit with the welder.

 

[2Wheel-Lee]

Make sure you use locktite on the front. The field is seeing the drain bolt come out when it takes hits on rocks or whatever. I had the shop give it a hit with the welder.

Though it is debatable if the front drain plug is even needed, I just unthreaded mine one turn, and then hit it with a flapper wheel so it was flush with the dif, then tightened it back up. No worries of it coming unthreaded on a rock now.

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