billscamaros

iTrader: (1)

On my commute this past Friday, the Z developed a whine in the rear end. It almost sounds like a tire going bad, but I swapped the rears for the fronts and the sound remains in the rear end.

I checked the diff fluid this weekend, and it was low. I added about 1/2 quart to the differential.

The whine remains the same.

So could I have damaged the rear end gears? I realize that it could be a bearing.

I guess that my question is: if I continue to drive it, can I assume that whatever is wrong will gradually get worse? Do I have to worry about a catastrophic failure?

Thanks

FirstYrLS1Z

iTrader: (4)

A low(not virtually empty)fluid level will still apply lube to the ring gear as it rotates(not saying the gears didn't go bad). Since the ring gear is getting lube,so will the pinion as it meshes with the ring gear. The flinging of lube off/from the ring gear will also throw some lube to the passages that go to the pinion bearings.
What's affected by low level is the carrier internals,carrier bearings,and axle bearings.
I drove for 4 years with a growling passenger side carrier bearing,caused by low level in 2003,and didn't replace it until 2007.

billscamaros

iTrader: (1)

This coming weekend I plan to pull the diff cover, replace all the fluid and add new GM diff lube. The whine has remained constant during my commute, so I'm hoping that no bearings are totally wrecked.

tmdz28

iTrader: (2)

does it only whine at higher speed? cause i hear whines starting at 40mph, and gets louder as the speed increases. in my case though, i am suspecting it is the bearings.

or so i hope.

Ls1guy98

if the carrier bearings are bad, which i hope they are not don't worry about it i drove my old lt1 till the rear was literally howling so loud it sounded like a jet taking off! And it still didn't blow by the time i replaced it. These rears are junk anyway i would drive on it and save cash till you got enough to buy a 12 bolt or a 9in.

billscamaros

iTrader: (1)

tmdz28 - the whine that I can hear begins from idle and continues up to the higher revs. it has a "whurrr" sound to it. the whine remains the same at speed, even when i push the clutch in or apply the brakes. no change.

ls1guy - yeah, i realize that the whine probably indicates a bearing going bad and that it could take some time before it fails. honestly though, just knowing that it's not right will drive me crazy and i'll have to get it fixed.

alamantia

iTrader: (10)

Sounds almost like an axle bearing, their cheep.

cDorch

iTrader: (3)

my rear started whining subtly like youre talking about around 2 weeks ago...as of now it whines so ridiculously loud i cant even drive it lol if i were you i would keep driving it until it gets bad and at the same time be on the lookout for some deals on a new one

billscamaros

iTrader: (1)

I changed the rear diff fluid, including the GM diff additive, today. The whine still persists.

I found this "t" shaped piece of metal in the bottom of the diff ..... anyone know what it is???





Here is the metal that was caught by the magnet inside the diff cover. The car has 220K miles on it.

billscamaros

iTrader: (1)

The "t" shaped piece of metal must be a part of a bearing race.

Since there is no change in the tone of the whine when I push the clutch in and coast, can I assume that it's not the pinion bearing? (if it is the pinion bearing, can I simply pull the pinion out from behind, and replace the bearing?) It would have to be one of the carrier bearings?

Are the axles held in place by "c" clips these days, or are they bolted in at the axle flange?

Thanks

dgcustomz

iTrader: (127)

That's not part of a bearing race, it's part of the needle bearing cage. Thats actually part of the cage that holds the needles in place. Best thing to do is to pull the carrier out. Check to see if both bearings on the carrier are ok. If they are ok, then most likely its the inner pinion bearing. If it comes down to removing the pinion then you will need to replace the crush sleeve. Before removing the carrier make sure you seperate the factory shims on the carrier and label them to what side they came off. If you put the wrong one on the wrong side you will change the backlash. If you need any more help just post up!

dgcustomz

iTrader: (127)

I forgot to answer one of your question. It has a bolt in the middle of the carrirer that holds in the pin for the axles. Remove that bolt, pull out the pin and push the axles in so the c-clips can come off. If you have a 4 channel rear end, make sure you remove the abs sensors before pushing the axles in.

billscamaros

iTrader: (1)

So ... driveable or not? My round trip commute is 120 miles. I'll plan to have it taken care of this coming week, but I do need to get to work.

dgcustomz

iTrader: (127)

To be honest, I wouldn't drive it that way. Once the needle bearings come loose from that broken cage they will cause some damage. It can damage your ring and pinion. Then you will have to buy a new gear set. Also, alot of bearing failures that come through here have been towed to our shop. If it is the pinion bearing and it completely goes out then it gives it enough play to keep your car from moving. You will here alot of grinding, basically your pinion is eating your ring gear. 120 miles is a long way and I would not risk it.

billscamaros

iTrader: (1)

Thanks dgcustomz .... I dropped the car off at a shop tonight. I'll shift to the Suburban for a few days.

billscamaros

iTrader: (1)

So in the end, the pinion bearing was shot. I had the pinion bearing and the carrier bearings replaced. The car is back on the road, at 219,835 miles.

I do have a continuing question on the rear end, though.

This is a '99 Z28 M6. As such, it would have a limited slip differential - right? I guess that I thought that the posi-traction unit would have had several clutches in it ..... but this isn't the way these differentials work now?

The mechanic mentioned that since the differential does not contain any clutches, it does not require the GM differential additive. Is this correct?

Thanks

dgcustomz

iTrader: (127)

He's correct, you have a torsen unit. Gear driven instead of cone clutches like the auburn.

billscamaros

iTrader: (1)

Thanks. I drove it this morning to work without having to listen to any abnormal noises. The odometer shows 219,910 miles ..... I'll hit 220K tomorrow. This has been an awesome car!! Thanks to everyone for their help.

GravZ28

If you don't mind me asking, how much did it run you to replace your pinion and carrier bearings. I have an 01 Z28 and I have a whine when my car is in reverse and a low toned clicking when making turns coming from my rear end. The whine could be going when I am driving but I am unsure because my exhaust is too loud to hear it. Any advice is appreciated.

Tom Brunas

my 99 z I just bought says it has the 272 gear on door sticker, how do I check if this is true or not for myself since it has mods done to it?