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Discussion Starter #1
I dropped off my JK this morning to have the gears upgraded to 5.13s. I'm pretty happy it's finally happening, but I'm a little apprehensive considering everything that can go wrong with gears.

I've read a few different methods for gear break-in over the last few months. Anyone want to share any wisdom on the matter?
 

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WERE DID YOU GET GEARS FROM!!!!!!!!!!!!!!!!
 

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Discussion Starter #3
:lol: I knew that was coming! I ordered them on April 16. They were on backorder then (at least one set, the rears were). David at Northridge went searching when it became clear that no information was forthcoming. Luckily he was able to find a few sets -- I'm pretty sure he took a loss on the deal. I finally got them around June 15.
 

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Break in is simple. Make short trips (20-30 minutes), very your speeds, let them cool down before driving again. Do this for 300-500 miles, then change the gear oil and everything should be fine.
 

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Discussion Starter #5
I think that is the simplist method I've heard so far.
 

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drive agresively for the first 500 miles

thats how i have always been told to break in my gears

then change fluids after 500 miles, inspect the gears, and you should be good to go


have done this past 3 gear swaps and have never had issues

the most important thing is to have a quality installer
 

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I know how this sounds but my dad is a great gear installer and he always tells the customer the same thing

Don't tow or offroad for the first 500 miles.
After the 500 miles pull the cover and change oil, check for excessive metal shavings.
Fill here up and your good to go.
 

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Break in is simple. Make short trips (20-30 minutes), very your speeds, let them cool down before driving again. Do this for 300-500 miles, then change the gear oil and everything should be fine.
That's essentially what I've done. I heard that varied speeds is important, ie dont' go on a 500 mile interstate roadtrip at 65MPH!
 

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those who believe you need to "break-in" gears say that constant speed is the biggest killer of gears over the first 500 miles. i change gear oil after 150 miles, and don't drive for more than 20 minutes at a time during the first 150 miles. i change the gear oil again at 500 miles.
i recommend not driving over 50mph for the first 150 miles.

it might also be recommended to not tow anything for the first 500 miles. then, for the first 45 towing miles, go for distances of less than 15 miles, then stop and let the diff cool before starting up again.




with all that said, i also know people that say that gear "break-in" is b.s. the thought behind "break-in" is that because you have two surfaces that wear against each other and when parts are new, those surfaces don't match up perfectly. the heat cycles during the break-in procedures are thought to allow for the surfaces to establish a perfect match and a controlled wear pattern that have the same pattern at all speeds and loads (hence varying the speed for 500 miles).

the people who think you don't have to "break-in" gears say that the metal on the gears has already been heat-treated from the factory, and that they were heated a hell of a lot hotter than you driving on the gears can make them. essentially, they say the heat from driving on the gears isn't hot enough to matter, so no break-in is not necessary.

i do it anyway, just to be on the safe side. i also know guys that have installed gears one day, then ran the hell out of them the next with no problems.
 

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On a new vehicle, there is no recommended gear break in. That is the biggest argument against gear break in.

That said, I have always carefully followed the recommended break in on new gears.:smokin:
 

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Discussion Starter #11
On a new vehicle, there is no recommended gear break in. That is the biggest argument against gear break in.
I was wondering the same thing. But, at the cost of gears and the installation I'm not willing to take the chance.
 

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How can I get in touch with Dave at Northridge??? I want to order gears. Is he a member here?
 

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thanks!!
 

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Gear break in and brake break in are similar concepts.

Yes, they work right out of the box from the factory...but, when you CHANGE to a slightly different set up (Different ratios, different shoes or pads, etc....) they WILL mate a bit differently.

When I do an infrared shoot on a new gear set vs a broken in set...the new set ALWAYS runs hotter.

The set cools with time, hence the ~ 500 mile "take it easy" admonitions that you see so commonly.

The varied speed, and load, recommendations, are also to help (Mostly on a microscopic basis) with the mating of meshed surfaces.

I also found that its best to do the break in with good 'ol Dino juice, NOT synthetic oil.

When using the synthetics, the wear just doesn't occur in a measurable fashion at the rate it does with the Dino Juice.

So - Break in with Dino Juice, and when running doesn't heat things up anymore than normal....swap in some good stuff.

That way, the gears break in properly in the beginning, but then almost stop wearing after that.

:D
 

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Discussion Starter #16
How can I get in touch with Dave at Northridge??? I want to order gears. Is he a member here?
Yup, he's at SEMA. However, you can order from the website and get a discount for the trouble of them not being there (use coupon code SEMA5).
 

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Discussion Starter #17
Gear break in and brake break in are similar concepts.

Yes, they work right out of the box from the factory...but, when you CHANGE to a slightly different set up (Different ratios, different shoes or pads, etc....) they WILL mate a bit differently....
Thanks for the information. That's one of the best explanations I've received on it.
 

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I also found that its best to do the break in with good 'ol Dino juice, NOT synthetic oil.:D
Won't this mess up the lockers? I know Jeep recommends synthetic fluid with a friction additive in the diffs.
 

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Discussion Starter #19
Won't this mess up the lockers? I know Jeep recommends synthetic fluid with a friction additive in the diffs.
No. Differentials with the limited slip differentials require an additive to the oil, but the gear oil does not need to be synthetic. The differentials with lockers do not need any additive.
 
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