gear whine troubleshooting

there are a bunch of threads on this and most seem to be unresolved.. but I wanted to see if anyone had any input.

2000 with an 8.25, 150k on it.

At speeds over about 45 there's whine from the rear diff, if I'm off the gas it's quiet, on the gas it's a steady high pitch WAAAAAAAAAAAH type noise, it's louder if I'm accelerating and louder going up hills.

I've swapped the fluid, didn't see any metal in it, bearings felt fine, put it back together and set the lash per specs and checked the mesh pattern, everything seemed fine.

It's been like this a year but I'm leaving for awhile and need the jeep to run reliably 800 miles from home. You think it's just plain olf gear whine or something I should be worried about?

there's no fluid leakage or play at the pinion, all the u-joints feel good, short of swapping all the bearings or the axle I'm out of ideas other than drive it until it breaks

did you have it leak out dry at one point? i had a dodge ram 50 and the pinion seal went bad. leaked it all out and would wine like a bad dog. after i replaced the fluid and seal it would still wine. mainly due to the bad wear on the gears.

BenDiesel said:

did you have it leak out dry at one point? i had a dodge ram 50 and the pinion seal went bad. leaked it all out and would wine like a bad dog. after i replaced the fluid and seal it would still wine. mainly due to the bad wear on the gears.

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Not to my knowledge, when I took the cover off it had been sealed with RTV so I don't know if they come that way or someone had drained the fluid, but it was full and appeared to be OK.

Now that I think back one of the spiders had a little nick on one of the teeth, it wasn't enough to worry me at the time, maybe it should :gag:

I can probably pick up a used axle for $50 and swap it in but I don't have much time and I just don't want the thing to grenade on the freeway and leave me stranded.

you shouldn't have any problems from the spiders unless your going around corners or preforming a "one wheel wonder"

BenDiesel said:

you shouldn't have any problems from the spiders unless your going around corners or preforming a "one wheel wonder"

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hehe.

It's silent around corners anyway.

I really tend to think it's just a noisy gear set but a second opinion always helps.

I would say the ring and pinion are not tracking right because of gear wear or worn bearing. you would have to take the cover off and see how the gears are tracking or any loose parts. Good luck

tomhil said:

I would say the ring and pinion are not tracking right because of gear wear or worn bearing. you would have to take the cover off and see how the gears are tracking or any loose parts. Good luck

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Everything looked OK when I was in there, I pulled the carrier and looked at the bearings and put it all back in and set it up again and checked the mesh, it looked fine to me but I don't have much diff experience.
There's no abnormal wear on the ring gear, no wear at all that I remember.

if it's not tracking right is there any real danger of it going horribly wrong?

Really bad.... not really or it would have already happend. Its amazing how sensitive gears are, even the slitist wear or out of spec can cause problems.

What will happen is it will get worse and worse. So did you use diff gear pain ( thats what i call it ) and see the tooth pattern was riding in the middle of the ring gear, and how deep and shallow it was riding?

I would also take it out of park, Go underneath ( safty first ) and see how much your drive shaft can rotate with you hand. It shouldnt have very much play in it at all. if it does its very posible its out of spec, there is gear wear, or a bad pinion bearing.

Let me know, Good luck

tomhil said:

Really bad.... not really or it would have already happend. Its amazing how sensitive gears are, even the slitist wear or out of spec can cause problems.

What will happen is it will get worse and worse. So did you use diff gear pain ( thats what i call it ) and see the tooth pattern was riding in the middle of the ring gear, and how deep and shallow it was riding?

I would also take it out of park, Go underneath ( safty first ) and see how much your drive shaft can rotate with you hand. It shouldnt have very much play in it at all. if it does its very posible its out of spec, there is gear wear, or a bad pinion bearing.

Let me know, Good luck

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yes I used what I had, an old tube of red lipstick :rofl: and the pattern was perfect. I'll see if I can find the pics I took.
there's a little play in the shaft, maybe 1/8" or so

Putting the wifes lipstick to good use, hehe.