Breaking in new gears

[MojitoJLUR]

Just got 4.88 gears installed on Friday and have a question on the break in. My installer and everywhere online talks about standard break in process which I'm following. However, what about the front? I'm never driving in 4wd. How can I be sure those are broken in? Should I find a straight road and put it in 4 high?

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[chevymitchell]

Just got 4.88 gears installed on Friday and have a question on the break in. My installer and everywhere online talks about standard break in process which I'm following. However, what about the front? I'm never driving in 4wd. How can I be sure those are broken in? Should I find a straight road and put it in 4 high?

You don't have to do them at the same time. You can run the Jeep in 2 HI and then change the fluid in the rear and do the inspection. Then whenever you come back from your first 4 wheeling excursion, change the front fluid and do the inspection.

Honestly, all the gear sets I'v done, I put the vehicle in 4 HI and drive it down a straight road and listen for whining, grinding, and general noise. If there is none, you're good to go. Drive the Jeep and change the fluid after 500 miles or so. Once you've gone off-road a bit, then do the front fluid.

It's easy to get nervous and wrapped up in breaking gears in properly, but they're a massive chunk of metal that will take thousands of miles to develop a lifetime wear pattern. The break in is really to make sure bearing pre-load is set properly and to wash all the parts with new oil to get any debris and excess metal from the initial installation out.

You can break the gears in on the trail. There's no reason to take it slow after the initial test drive to make sure pre-load is right and that there's no unusual noises. You will want to cycle the lockers several times. The locking plates and solenoid must come off if your installer changed the smaller carrier bearing.

 

[MojitoJLUR]

You don't have to them at the same time. You can run the Jeep in 2 HI and then change the fluid in the rear and do the inspection. Then whenever you come back from your first 4 wheeling excursion, change the front fluid and do the inspection.

Honestly, all the gear sets I'v done, I put the vehicle in 4 HI and drive it down a straight road and listen for whining, grinding, and general noise. If there is none, you're good to go. Drive the Jeep and change the fluid after 500 miles or so. Once you've gone off-road a bit, then do the front fluid.

It's easy to get nervous and wrapped up in breaking gears in properly, but they're a massive chunk of metal that will take thousands of miles to develop a lifetime wear pattern. The break in is really to make sure bearing pre-load is set properly and to wash all the parts with new oil to get any debris and excess metal from the initial installation out.

You can break the gears in on the trail. There's no reason to take it slow after the initial test drive to make sure pre-load is right and that there's no unusual noises. You will want to cycle the lockers several times. The locking plates and solenoid must come off if your installer changed the smaller carrier bearing.

Thanks man. Next weekend we're going on a wheeling trip. I am trying to get to 500 miles before going so I can change the fluid. Would you say I should only change the rear before going and then the front after or both before and then the front again after?

 

[chevymitchell]

Thanks man. Next weekend we're going on a wheeling trip. I am trying to get to 500 miles before going so I can change the fluid. Would you say I should only change the rear before going and then the front after or both before and then the front again after?

If you're hitting 500 miles before going on your trip, change both before.

Just make sure you test the front diff under light load during your first 500 miles. (Includes cycling the locker)

You'll burn up your fluid if it isn't changed before you go. It would be ok and the Jeep would survive, but I would recommend going wheeling, on a fresh set of gears, with fresh fluid.

 

[MojitoJLUR]

If you're hitting 500 miles before going on your trip, change both before.

Just make sure you test the front diff under light load during your first 500 miles. (Includes cycling the locker)

You'll burn up your fluid if it isn't changed before you go. It would be ok and the Jeep would survive, but I would recommend going wheeling, on a fresh set of gears, with fresh fluid.

Perfect, thanks! Appreciate it!

 

[anotherWS6]

I "broke in" my 4.88's in my pickup by putting them in and driving it. Swapped rear fluid at about 10,000 miles. Have yet to touch front. Dont worry about it.

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