Whining noise from rear end. HELP

[winstonridingon24s]

There is a whining noise from the rear end ( rear axle assembly / differential ) of my girlfriends 2000 gmc safari van. It only makes this noise when the van is moving, no matter what gear you are in. The faster you go the louder it gets. I replaced the rear wheel bearings and oil seals for both rear axles, but it did not stop the noise. The gears in the differential do not look damaged and there was no pieces of metal in the differential when I opened it. Put everything back together and filled up the lubricant. From insde the van the loudest point seems to be right where the driveshaft attachs to the rear diff. Or maybe from inside the differential. Its hard to pin-point exactly. A friend thinks it might be the passenger side rear axle, that if it was a little bent , it would rub against the inside of the rear axle housing when the axle was spinning creating the whining noise. Its slightly louder toward the passenger side I think , hard to tell. Also my girlfriend said it has made the whining noise for at least 2 years, and she has never had anyone look at it. But before I waste more money replacing parts that don’t fix the problem, I was hoping someone might help me.

HOPEFULLY KNOW THE ANSWER!!!
Thanks, winston

[2.2 Straight six]

you've replaced the wheel bearings, so it's probably not that. but i'm guessing it's possible that it's a bearing inside the diff.

what's the milage of the van?

[curtis73]

Rear gear whine, I'm sure of it. As they wear they basically increase their tolerances and start whining. I have several GMs and they all start whining at about 100k depending on several factors.

The only way to really change it is to swap out the gears, but I'd seriously consider just putting up with it. Maybe you could buy a complete junkyard rear axle and swap it in. That would save you some money, but its a crap shoot... maybe the new axle would be worse than your current one.

Sometimes you can change the whine (or reduce it) with different lube. Try 80w90 instead of the 75w90 that GM recommends. If that helps, there is always 80w140, but that is pretty darn thick stuff. I wouldn't use it in a limited slip rear or in very cold climates, but it might shut it up.

[2.2 Straight six]

Originally Posted by curtis73

Rear gear whine, I'm sure of it.

do you mean the actual final drive gears in the diff?

[winstonridingon24s]

The millage on the van is about 107,000 miles. When I inspected the diff. gears they looked fine, not damaged at all. And I mean the ring and pinion gears, spider gears also known as the diff. pinion gears , and the diff. side gears. By saying diff. pinion gears I mean the small 2 gears on top and bottom of the pinion shaft, that lock together with the 2 small gears on the sides or the diff. side gears. All 4 small gears inside the diff. case. But all of that looked fine. Is it hard to tell if the gears are in good or bad shape by spinning , and looking at them. would it be easy to mistake bad gears because they looked good. How many different bearings are inside the rear axle assembly ( the entire rear end ) anyway. I just cant get it out of my head that when something that spins alot on a bearing starts to make a whining noise that means the bearing is wearing out. Is there a test or inspection I could do to know for sure what the problem is ,I mean is there a way to narrow it down through a process of elimination, or something to 1 or 2 parts that had to be the problem.

[curtis73]

Nope, the actual gears themselves, in specific the ring and pinion. Mine whine like a spanish whore after 96,000 miles.

They don't have to be damaged, they just wear and their tolerances increase and bingo, they whine. How often was the rear gear lube changed?

It doesn't have to be a bearing. Even if you have a brand new axle and you switch ratios before installing it, if you don't get the pattern and pinion depth just right, they'll whine like nobody's business. Its the alignment and clearance of the ring and pinion, not the bearings.

The bearings make more of a grind, vibrating noise, almost like knobby tires. Gear whine sounds like a low whistle

that axle should have 6 bearings; two on the pinion, two on the carrier, and two out the axle tubes.

[winstonridingon24s]

The lub has most likely never been changed until now, knowing my girlfriend. The engine blew up in her last car because she never put oil in it. So I seriously doubt that any maintenance has been done ever, except changing the oil. The only reason she does that is because what happened before. She is your basic dumbass, but her body and looks more than make up for the missing brains. And I guess I was wrong in describing the noise as a whining, because it sounds identical to big mud tires.

[kevinthenerd]

Originally Posted by winstonridingon24s

The lub has most likely never been changed until now, knowing my girlfriend. The engine blew up in her last car because she never put oil in it. So I seriously doubt that any maintenance has been done ever, except changing the oil. The only reason she does that is because what happened before. She is your basic dumbass, but her body and looks more than make up for the missing brains. And I guess I was wrong in describing the noise as a whining, because it sounds identical to big mud tires.

You'll be single if she reads this. You know that, right?

I'm glad I have a smarter girlfriend than that. I do the maintenance on her car, but she's smart enough to at least remind me. Oil is cheaper than metal, if you really think about it.

[UncleBob]

rear end whine is almost always the pinion bearing.

The quick test is to grab the drive line near the u-joint and try to move it up and down. If it moves at all, suspect the bearing.

But even if it doesn't move, I'd still say: pinion bearing.

BTW, take it to a rear end shop. You don't even want to get into doing a rear end. They aren't hard, but require experience and a small number of special tools. But the experience is what you're really paying for.

[JustSayGo]

I agree with Unclebob. Sounds like you are describing noise from the front pinion bearing. The bearings should have pre-load. If you can wiggle the pinion at all, the pinion bearings are worn. Gear noise is often most noticeable around 45mph and the pitch of the noise will change as you accelerate or decelerate. Pinion bearing wear will also change the clearance between the ring and pinion and cause gear noise. New gear teeth have lines that run across the teeth. Worn gears will have bright shinny teeth that have worn through the lines and still appear undamaged. Teeth with 100k could very likely still have those lines. Careful inspection of gear teeth would involve good lighting and possibly a magnifying glass. Are the rear axle bearings strait rollers that use the axle as the inner bearing race surface?

[534BC]

I'd also agree. Pinion bearings.

[Labrat0116]

Ok, I have a 2012 Jeep Liberty with 8,000 miles on it were the gears have whined since I took it off the Dealership's lot with 12 miles on it.

I seriously doubt there is anywhere on the rearend components. Most likely the gear lash is off a fraction of an inch.

It's going to the shop soon to get checked out. Yea, I know it's been awhile..... LOL!