xj regeared

I'm picking up my jeep tomorrow from getting it regeared. I've read not to let the gears over heat, and to stop to let them cool down after the first 20 minutes or so. The shop is supposed to take it out on a test drive before i pick it up, but I still have about an hour drive back home. It is around 50 miles.

My question is, on the way home should I stop for a half hour or so to let the gears cool down, or just drive all the way home? Then I know to change the fluid around 500 miles. I have an ARB f/r in a 30 and a toy 8.4. Can I use the same weight(what weight?) in both axles, and should I use synthetic with the ARBs? Finally, for the 500 mile duration, should all of my time driving be under the 20 minutes, or can i increase my drive times?

thanks

When I got my gears installed, my first break-in was to the trails. About a 60 mile drive. I got there and let the Jeep sit until the axles cooled. Also, check the ARB manual for what weight oil to use. It depends on your driving style/climate.

Technically, you shouldn't even take it on the trail (unless it's some light stuff) until after the 500 mile break in. Some heed the advice, some don't and I suppose who manufactures the gears makes a difference too.

Be kind to yourself, about halfway home the first time, stop, take a leak, get a soft drink and check out the chicks. After that you should be OK. It doesn't hurt to be on the side of caution the first time.

How do you break in the front diff? You clearly wouldn't want to drive 500 miles on the street in 4WD? When I had mine done, I asked the shop what to do about the front diff breakin, and they said drive it lightly on some gravel roads in 4WD as much as you're willing to tollerate, but hard to get 500 miles of that.

Planetcat said:

How do you break in the front diff? You clearly wouldn't want to drive 500 miles on the street in 4WD? When I had mine done, I asked the shop what to do about the front diff breakin, and they said drive it lightly on some gravel roads in 4WD as much as you're willing to tollerate, but hard to get 500 miles of that.

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Couple of decent wheeling trips (not hard, thrashing ones) and you should be fine. Change the fluid and carry on.

:wave: Go by the manufacturer recomendations on the weight and type of the fluid.

I just installed completely new axles in my xj and what I did for break in was drive it at different speed in town and on the highway for a short while to the trail and then wheeled them hard. This way you dont get the heat and ware pattern in the same spot on the gears. By going different speeds you increase and decrease the amount of heat and where you put it on the gears.

As for the front gears, you won't be going cruising speeds for any long distances for long so that will help and as you wheel it they will break in over time.

I will tell you though ever since I started fixing stuff. To check it out and break it in I ALWAYS DRIVE IT LIKE I STOLE IT!! :flamemad:

If it is going to break, it will do it from the get go, if it doesn't break, well, you are good to go. This has always worked for me and I have found that I am usually good to go.

thanks for the tips guys. i'm getting ready to head out and pick it up now.

Ok,
I will start by say that you need to try and follow the break in proceedure that is given to you by the mechanic that did the install. That being said, don't wheel it like you stole it. racing around at speeds keeping the gears loaded up is going to overheat the gears. In the same breath, don't drive like grandma either.
wheeling in the first 500 miles is fine if the type of wheeling you do is slow speed crawling stuff. Dune running and muddin' are no-no's because your required to keep up wheelspeed which requires power. and I would try not to go out and run johnson valley hammers. stick to a light/medium trail that offers scenery.
the majority of the breakin happens in that first 15-20 minute drive. even though the gears are hardened and prerun, face of each tooth needs to be work hardended beyond that of what a machine can do.
since I am a gear installer, I have my own methods that have worked so far without any bad gearsets.
I personally do the first 15-20 minute drive. Some hard acceleration and decelleration. some figure eigths if there is a locker or posi. about 3-4 minutes on the freeway at 70ish mph. and some normal stop and go.
then I go put my hand on the rear diff, its usally very hot to the touch to where i can't keep my hand on it for more than a few seconds if that. Thats my indicator... my hand. then I let the rear completely cool for 3 hours during which time I regear the front axle.
my suggestion that I give to the jeeps owner is like this.
Drive the first 30 minutes on the freeway home, then stop and eat dinner. when you stop, check the rear diff with your hand, it should be pretty hot and you have to pull your hand off after a few to several seconds (2-7seconds usually). if its really hot, then let it cool for a while, if its not hot and you can keep your hand back there for a bit (more than 5sec) then you can continue to drive home. see where I am going with this. as your gears get broken in, they will not get as hot each time you drive it.
and when you get home from having them installed, be sure to let them cool for at least 3 hours.
as for the front axle. if you have vac disco, then you will atleast need a little bit of driving in 4wd on a graded dirt road. with no vac disco, I recomend changing the fluid at 1000 miles but you can wheel hard after 500.
I had one axle come back after a few weeks. turned out that he took it to the dunes only a week and a half after I setup the gears and locker. he overheated the oil, which allowed the inner pinion bearing to aneal and lose material. this loosened the pinion depth which caused the noise. needless to say, he voided any warranty on both axles and had to pay for a new bearing and the time it to me to find and fix.