Specific Gear Break In Question. Long way from the shop!

I searched a few terms, and the closest thread was this one...

http://www.naxja.org/forum/showthread.php?t=46690&highlight=gear+oil

I've also read elsewhere about "burn in" or something like that. In general people say after the gear swap, drive it about 30 miles, check the diffs (and drain and refil them? or what?)

I am getting my XJ regeared (planning to) at a shop 3 hours from my home.

I'll ask the mechanic again to define what he means by "I'll burn them in for you..." after I told him "Remember, this thing has to be spot on, I gotta drive a long way home."

So anyway, if you were doing this, what precautions would you take when picking up the ride. What would you bring along for the trip home?

Thanks for helping a noob.

I'm gonna search some more and see if I get better hits.

I had to drive my Jeep ~120 miles home the first day, and then another 250 the 2nd day. I stopped twice on the way back (the first day) and let it cool for at least 20 minutes each time.

It's worked fine so far (2000 miles on it or so.)

I flushed it the next weekend with about 800 miles on the rear, haven't gotten around to the front yet.

Yeah, my understanding is to drive it for 30 minutes at a time, stop and let it cool down. Then change the gear oil after 500 miles.

The mechanic will probably "burn them in for you" by doing donuts in an empty lot. I've heard of someone doing this.

So you're gonna be stopping several times on your way home. I would bring along tools, gasket maker, and extra gear oil. Just in case you develop a leak.

I'm having my gears done tomorrow. Luckily, my buddy who's doing the gears only lives about 20 minutes from me.

Donuts? I was thinking run it while it's still on the lift for a while, but donuts sound like a lot more fun!

just be sure to change it after about 500 miles, i did my rear that way but waited a good deal longer for the front. one of the bolts was stripped and that was my excuse i suppose to put it off for a couple extra weeks. anyways once i popped the cover it was pretty nasty in there. lot strange colored thick fluid mixed in, almost as if it had gotten water in it.

wescam said:

I searched a few terms, and the closest thread was this one...

http://www.naxja.org/forum/showthread.php?t=46690&highlight=gear+oil

I've also read elsewhere about "burn in" or something like that. In general people say after the gear swap, drive it about 30 miles, check the diffs (and drain and refil them? or what?)

I am getting my XJ regeared (planning to) at a shop 3 hours from my home.

I'll ask the mechanic again to define what he means by "I'll burn them in for you..." after I told him "Remember, this thing has to be spot on, I gotta drive a long way home."

So anyway, if you were doing this, what precautions would you take when picking up the ride. What would you bring along for the trip home?

Thanks for helping a noob.

I'm gonna search some more and see if I get better hits.

Click to expand...

The Yukon guys recommend to drive 15-20 miles and let cool. Do this a few times. Make sure to run 500 miles or so before towing or heavy usage. This will let the ring and pinion seat together and reduce your possibility of melted gears (not too common). I like to keep an eye on the heat that the pinion bearings are generating, and the overall gear housing/oil temp. If new, the pinion bearings especially will get quite warm during the first 200 miles or so. They should not get too hot to touch, as it may induce premature bearing failure. (This condition most likely is caused by excessive pinion bearing preload.) The axle should gradually cool down to a temperature that's warm to touch after break in (500 miles or so). It should never be cold though! I'd recommend swapping the gear oil after 500 miles or so. This will flush any junk, metal particles, or foreign chunks that may have found their way into the housing from either the new gears/bearings or who knows where else? You don't want junk getting ground into new bearings! I have had excellent results with my gear swaps! If they are setup right, they should be the last thing to fail in the drivetrain Good Luck!

FUNKYTEE5

I had a 100 mile drive back from the shop after my regear. I went with the 15-20 miles at a time and then let it cool down routine. (Recommended by Randy's R&P) It took me 7 hours to get home because I waited until diffs were cool to touch, but the time was insignificant compared to the cost of the regear.

Take a book, or some good tunes with you, I was bored to death waiting for the diffs to cool.

John

Crap, going to be a long day, but I did the Sirius Radio mod first, so I should be good to go. Sounds good. Just lots of stops.

It's 230 miles (roughly) so he will have done it some and I'll do stops every 30 miles or so I suppose. At least for a while to check things.

Thanks for the information. I thought it was going to be like a few gear oil changes to get back. But I read some more and 500 miles seems to be the # from the manf. and what others did.

I just took mine for the 15 mile initial break-in ride, and drained the fluid as soon as I got home and let them cool down. Tomorrow I'll put the covers back on, and drive it for 100 miles and change the fluid again. Gear oil and gaketmaker are cheap compared to re-doing the gears again. Change it sooner than later to keep the break-in metal chips from damaging the gears.

lot strange colored thick fluid mixed in, almost as if it had gotten water in it.

Click to expand...

The fluid had changed color similar to having water in there. This was from the pattern checking paste mixing in with the oil.

good to know it wasnt anything to bad

Yup found what GI-John was talking about on Randy's Ring and Pinion (duh, should have looked there first eh?)

"Even with synthetic oils, I still recommend the following procedure for breaking in a new gear set: After driving the first 15 to 20 miles, stop and let the differential cool before proceeding. Keep the vehicle at speeds below 60 mph for the first 100 miles. I also recommend putting at least 500 miles on the new gear set before heavy use or towing. During the first 45 miles of towing, it helps to go about 15 miles at a time before stopping to let the differential cool for 15 minutes before continuing. This is necessary because not all of the gear tooth is making contact until it is heavily loaded. When towing, the teeth flex to contact completely, and cause the previously unloaded portion of the teeth to touch and work harden. It is very easy to damage the ring & pinion by overloading before the teeth are broken-in. If you take it easy on a new ring & pinion and keep it full of high quality oil, it will last a lot longer. "

In case anyone else was interested.

FWIW, I also drove it back in Full Time 4wd to break in the front diff also.

Take a few gallons of water and a spray bottle with you for your ride home....that will get the housing cooled down faster.