Breaking in New Gears on a front axle, right way

[mrdrnac]

I looked on the internet and found differing opinions (what a surprise) on the correct way to break in new gears on a front 4x4 axle. Can you just put the Bronco in 4X4 Hi without locking the hube and drive it easy for the first 15 to 20 miles and then let it cool; or does this not load the gears enough and you need to go to a trail and actually run in in 4 wheel drive with the hubs locked?
Thanks!

 

[JWMcCrary]

I've never worried about breaking in front gears. Bolted it up and used it like normal. A set I put in 2005 looked great the last time I looked at them. I wouldn't over think it, others may disagree. But I'm sure you could find specs for tightening a battery cable too.

 

[Broncobowsher]

For the front axle I am going to say it really doesn't matter. They really don't need a break in like an engine does. Or even a rear axle.

Without putting a load on them there really isn't any break in happening.

If I had to break in a front differential, I would do it by removing the rear driveshaft and drive around in FWD. But that is beyond what a Bronco front axle will need. Unless running an NP203, in which case you will break it in along with the rear axle at the same time.

 

[DirtDonk]

I'd say it's not as important as well. After all, since you're driving on the "coast" side of the gears, and coasting on the "drive" side, it's kind of a moot point anyway. There's really no break-in that's going to give you some advantage over not breaking it in.

Or you could do it like many rear ends are done. Up on jackstands.
Just raise it up, lock it in, and run it at high idle in reverse for awhile (twenty or thirty minutes?) and then do the same thing in drive.

I have no idea if that has merit, but it seems like something I'd do just because I wanted to do something!

Paul

 

[mrdrnac]

Thanks Paul, my new front axle is a high pinion (sorry forgot to mention that) so it does run on the regular side of the gears. Like mentioned before, I am probably overthinking this, on my last gear change I just drove them and after 20 years both front and rear were still good, and I never even changed the gear oil!

 

[blubuckaroo]

The differential shop that changed my gearsets told me NO TOWING for the first 500 miles. They do get hotter when developing a pattern.
The front would be different though. Except for unusual circumstances, most fronts won't see the heat created by prolonged highway use.

 

[cs_88]

With twin sticks you can put the Bronco in FWD and take it for a spin.
This is what I did when I did my gears.
It was more of just a test drive than really trying to break anything in.