Question on "new gear" break-in.. Different scenario.

[Skwerly]

20 mins on then 20 min off.

in other words...
Drive 20 min then cool 20 min. Do this 3 times.
Then at 500 miles change oil by Pulling Cover.

For that first 500 miles there shold be no shock loads, or towing with the vehicle.

This is the proper way.

How you break in or broke in your gears is completely up to you, of course, and failure is NOT guaranteed, but it's also not a guarantee that you'll die if you shoot yourself in the head. Still, it's never a good idea to do so. Stay safe, keep care of your equipment, don't listen to tall tales or follow other people's mistakes, which is exactly what those are.

 

[jeeperjohn]

This is the proper way.

How you break in or broke in your gears is completely up to you, of course, and failure is NOT guaranteed, but it's also not a guarantee that you'll die if you shoot yourself in the head. Still, it's never a good idea to do so. Stay safe, keep care of your equipment, don't listen to tall tales or follow other people's mistakes, which is exactly what those are.

Right, the manufacturers have recommendations for a reason.

 

[RWKHausSupply]

And just how would you diagnose a set of gears that failed because they weren't broken in correctly. Prove that it wasn't a bad set-up to begin with. Do you just automatically suggest that the customer didn't break them in properly if they make noise?

I suppose all those people I set up gears on at the dealership must have screwed up their gears becuase they didn't stop after 20 mins to let them cool down. I don't remember learning anything like that at the factory training center either.


:dunno:

A bad set up doesn't "wear gears" unless the pattern is bad when it was initially setup, and that is 100% OBVIOUS to Any gear person. Yes the common denominator would be break in. Hot oil that has been broken down beyond its designed heat range, will Not lube the gears Or the bearings very well at all.

And if you work at a dealer then you should know its the vehicle design that typically has a inherently design flaw (IE ZJ or WJ Quadra drive) that causes excessively fast gear and bearing wear, that will commonly cause failures. I have not seen a bad gear set in over 2 years now. I don't know if maybe the aftermarket world has it right, now and dana or AAM or OE in general, haven't figured it out, OR if its maybe the abuse a new vehicle is put thru from the get go, Or even the Lack of a owner's manual reading, is the main cause?

I cant say for sure if its in the new cars as of the last few years, but right in the owner's manual of new cars it clearly used to state to follow certain limitations to speed, RPM, etc.

We all know the "dealer" is the authority when it comes to anything drivetrain. But when Motive gear or Yukon gear or Any gear company says right in the literature that comes with the gears/install kits, to follow something for long life, then it must mean something?


In any case You can do whatever your lil heart desires...

But for me I recommend what the name on the gear box recommends. And that is "proper gear break in procedures". And if the customer doesn't follow it and has issues, I'm sorry. but at least he was given the Correct way to set, lap, cool the gear set. If it inconveniences him/her for a whole hour, I am sorry. but to me a hour is well worth the much higher Possibility of a lifetime of problem free differentials.

As for race motors being broken in on a dyno, thats very seldom. Its a great concept, but when your at the track how often do you see a team go back and pull a full motor and install a motor thats 100% assembled. thats a whole other thread though.

 

[Gaius]

I would just drive 30, let it cool, and the drive home. Check it a couple times during the drive though, feel the top of the diff, don't let it too hot to touch by hand.

 

[Bryan C.]

A bad set up doesn't "wear gears" unless the pattern is bad when it was initially setup, and that is 100% OBVIOUS to Any gear person. Yes the common denominator would be break in. Hot oil that has been broken down beyond its designed heat range, will Not lube the gears Or the bearings very well at all.

And if you work at a dealer then you should know its the vehicle design that typically has a inherently design flaw (IE ZJ or WJ Quadra drive) that causes excessively fast gear and bearing wear, that will commonly cause failures. I have not seen a bad gear set in over 2 years now. I don't know if maybe the aftermarket world has it right, now and dana or AAM or OE in general, haven't figured it out, OR if its maybe the abuse a new vehicle is put thru from the get go, Or even the Lack of a owner's manual reading, is the main cause?

So now the oil somehow gets hotter during break in, so much as to cause the oil the break down? Get real, I don't buy that one bit. Just drive the damned thing like you normally would. Nothing more.

As for the ZJ and WJ issues, those related to assembly of the axle at the Dana manufacturing plant. They liked to build the center section, and then press in the axle tubes after the fact. Get your facts straight.

I bet you're the type of guy that when you make a box of mac and cheese, you actually measure out the water to boil the noodles in. It says it right there in the instructions. What about your shampoo. Do you lather, rinse, and then repeat? It says so right there in the bottle?

 

[RWKHausSupply]

As for the ZJ and WJ issues, those related to assembly of the axle at the Dana manufacturing plant. They liked to build the center section, and then press in the axle tubes after the fact. Get your facts straight.

I was refering to the front end, NOT the aluminum D44HD... Which consistant drive causes the pinion bearings and gear sets to fail. I think I did 4 one month and 6 the next before I started turning them away, cause I know that even after I redo them they will fail again, and I dont wnt to, have to explain that to the customer when they return.

Again, back on subject, this isnt a shampoo or mac and cheese thread, right?

You can do ANYTHING your lil heart desires. But for me I will continue to tell ALL my customers the Correct way, the name on the box, says they want thier gear set(s) to be broken in... Thank you...

 

[vetteboy]

So what's so magical about 20 minutes?

Seems rather arbitrary to me.

 

[MoparManiac]

The first time I drove my MJ I accidentally did a reverse burnout for a few seconds (clutch pushrod wasn't long enough).

I then proceeded to chirp third gear in low range a couple times going up my driveway.

My gears must be screwed?

 

[Bryan C.]

Again, back on subject, this isnt a shampoo or mac and cheese thread, right?

You can do ANYTHING your lil heart desires. But for me I will continue to tell ALL my customers the Correct way, the name on the box, says they want thier gear set(s) to be broken in... Thank you...

I just thought that since you read and follow the instructions from every gear set you install, why would you stop at just the stuff you buy for your Jeep? If reading the directions have mnade you an expert at installing gears, I would only assume you would be an expert shampoo or mac & cheese guy as well. My apologies for that assumption.

 

[jeeperjohn]

So now the oil somehow gets hotter during break in, so much as to cause the oil the break down? Get real, I don't buy that one bit. Just drive the damned thing like you normally would. Nothing more.

As for the ZJ and WJ issues, those related to assembly of the axle at the Dana manufacturing plant. They liked to build the center section, and then press in the axle tubes after the fact. Get your facts straight.

I bet you're the type of guy that when you make a box of mac and cheese, you actually measure out the water to boil the noodles in. It says it right there in the instructions. What about your shampoo. Do you lather, rinse, and then repeat? It says so right there in the bottle?

I have set up dozens of diffs for folks in my area. Every time I change the oil after break in I can smell the difference in the oil from the heat caused during break in. I install strong magnets on the diff cover when I do gears to help reduce the heat generated during break in by removing the wear metal from the oil. Can you get away with no break in period? Maybe but is it worth the risk of having to pay to redo it all again? IMO no.

 

[jeeperjohn]

So what's so magical about 20 minutes?

Seems rather arbitrary to me.

That's the amount of time it takes for the gears to get good and hot during break in when the gears are "lapping" in to one another.

 

[scottmcneal]

Nice way to treat VENDORS on here. Guess you know more than he does.Again get job.When do i renew again?

 

[Bryan C.]

Nice way to treat VENDORS on here. Guess you know more than he does.Again get job.When do i renew again?

:laugh2::roflmao::laugh2:

Misinformation, no matter where it comes from, will be disputed.

I agree with the 500 mile fluid change, but not the ridiculous 20 min threshold that appears to have everyone's panties in a wad.

 

[vetteboy]

That's the amount of time it takes for the gears to get good and hot during break in when the gears are "lapping" in to one another.

I spent 20 minutes stuck in traffic today going a mile and a half.

Also spent 20 minutes completing a lap at the woods race I was in this weekend, which I'm sure was far more abusive.

So I'm assuming that's 20 minutes of continuous somewhat-gentle, constant-speed driving. There are zero roads around here that I can accomplish that on and I'm certainly not trailering it to someplace that I can.

I would also say that starting in the dead of winter vs. the heat of summer plays a part, the gears will definitely take longer to heat up if the gear oil's sittin at 0 degrees.

What does getting the gears to an arbitrary (and unknown) temperature have to do with the lapping process? Is there a critical temperature where lapping becomes more effective?

:dunce:

500 miles of holding back your right foot, change the oil, down the road.

 

[asp]

What happens if the gears get too hot while they are lapping in? Will the gears lap to the point where the backlash opens up out of spec?

 

[Gaius]

You just have to drive it moderately for a bit then let cool a couple times, this hardens the teeth face, essentially like heat treating it.

 

[vetteboy]

What happens if the gears get too hot while they are lapping in? Will the gears lap to the point where the backlash opens up out of spec?

Don't even get me started on cold lap and hot laps.

 

[Bryan C.]

You just have to drive it moderately for a bit then let cool a couple times, this hardens the teeth face, essentially like heat treating it.

:laugh2:

 

[Gaius]

:laugh2:

Orly? Glad I could make you laugh.

 

[NattyBoh]

What about thus guys. Being 4 wd how does the front gears lap? I'm guessing since the front is always spinning its still in contact, right?