4wd gear break in

[Stephen Carter]

So here in a week or so, I will be getting gears installed in my 10 bolts. Since these are manual hubs, how do I break in the front gear set? Do I have to drive every where in 4whi for 500 miles?

In case it matters, Yukon gears, 4.56 ratio. 10 bolts of course.

 

[Blue85]

I remember pulling my rear driveshaft and doing easy commuting for a while to break in my 4.10s. This is harder with a slip-yoke case, but can still be done. When I went 4.88, I put used gears up front.

Seems like the binding of 4x4 on pavement isn't the right usage for break-in. Running with 1 hub unlocked (or both) is not the right loading either.

 

[Fastereddie]

I have never worried about nor had an issue because of it. I dont know? They say not to tow for first 500 miles but a friend of mine bought a brand new dually and towed his fifthwheel across the country. No issues. Think he said he has 75k on it now.

 

[Bent77]

I don't remember doing any break in on these (in terms of gear sets) when the trucks were new

 

[sweetk30]

years ago were I use to work we did a gear swap for a guy running 46" tires in a 700+hp dodge cummins truck .

we told him to break them in and be easy . well I went for a ride with him

lets just say he broke them in just the way he was going to drive it . . . . never had a problem with them . and the cop's chased him on to his trailer and made him leave town . . .

 

[swettysblazer]

We normally tell people to drive the first 50 miles at highway speeds and let it cool down... Do the same thing for two or three cycles. THen flush the fluid at 500 miles. Now granted these are on mostly JK's, but it should be the same across the board.

 

[AV8TER]

What would be your process for this if you just bought a new rig off the lot? If you're like most people out there you would just drive it, right? I wouldn't tow anything heavy for a bit and just enjoy your new ratios!

 

[obijuank5]

It will probably be fine but read yukons break in reccomendations.

You're looking for hot and cold cycles to ensure you get a good set of gears for a very long time.

Take it easy on em and no Smokey burnouts and avoid excessive loads if possible. You're seating new bearings too. No reason to ruin em if you don't have to.

As an installer, we do a soft break in on the rack for you before it hits the ground. Then my test drives usually have them fairly broken in anyways.

 

[Blue85]

A new vehicle is not the same as new gears. They set them up and break them in before you buy it.

Used gears are similar - you have to set them up, but no real break-in required.

 

[Stephen Carter]

Thanks for all the replies guys. I went back and re-read the install and break in instructions. They say 15 to 20 miles, let the diff cool off, the basically drive like a granny for a hundred miles and no towing for 500. I can do the first two easy enough and well I don't plan on towing with this beast at any point really...

 

[6.2Blazer]

The original question was how to break in the front gears, which is a whole different animal because it is pretty hard to drive around on pavement with the front engaged. To be honest I wouldn't worry too much about the front end gears. The break-in just helps with long term wear and avoids the issue with them getting really hot if you drive for a long distance down the freeway at high speeds right at the beginning. Neither of these are really an issue with the front axle.