WTF is this noise?
Safety Car
Joined: Aug 2009
Posts: 3,751
Likes: 276
From: Melbourne, Victoria, Australia
noise. Universal joints tend to squeak, when needle bearings in cap are dry and rusty.
Don't forget to check tyres for uneven wear? has the wheel alignment shifted, is not common for the camber bolt to move. Look at the rear tyres that there is no obvious camber difference side to side, uneven toothed tyre wear can cause howling growling noises like bad wheel bearings.
Hope it helps narrow it down
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Melting Slicks
Joined: Nov 2016
Posts: 2,256
Likes: 3,082
From: So Cal
2023 C4 of the Year Finalist - Unmodified
If it only does it while turning and in both directions, it could be the posi clutches. If the noise is the posi clutches, they will only make the noise when there is a speed difference between the two rear wheels, like in a turn. They can't make noise running straight ahead.
. I had a similar noise in my 88 30 years ago when I used a parts store 80W/90 that claimed it had the posi additive in it already. It squealed like a pig when turning in either direction. The tighter the turn, the louder the squeal. I pumped that lube out and refilled with GM axle lube and 1 tube of the additive from over the counter at my dealer. Prior to then, and every posi axle since, all I'll use is the GM lube with GM additive. I tried "something else" once, and it caused noise. The GM stuff never has. YMMV.
. I had a similar noise in my 88 30 years ago when I used a parts store 80W/90 that claimed it had the posi additive in it already. It squealed like a pig when turning in either direction. The tighter the turn, the louder the squeal. I pumped that lube out and refilled with GM axle lube and 1 tube of the additive from over the counter at my dealer. Prior to then, and every posi axle since, all I'll use is the GM lube with GM additive. I tried "something else" once, and it caused noise. The GM stuff never has. YMMV.
Last edited by IHBD; Mar 27, 2025 at 06:54 PM.
Thread Starter
Pro
Joined: May 2021
Posts: 726
Likes: 113
From: Washington, Illinois
If it only does it while turning and in both directions, it could be the posi clutches. If the noise is the posi clutches, they will only make the noise when there is a speed difference between the two rear wheels, like in a turn. They can't make noise running straight ahead.
. I had a similar noise in my 88 30 years ago when I used a parts store 80W/90 that claimed it had the posi additive in it already. It squealed like a pig when turning in either direction. The tighter the turn, the louder the squeal. I pumped that lube out and refilled with GM axle lube and 1 tube of the additive from over the counter at my dealer. Prior to then, and every posi axle since, all I'll use is the GM lube with GM additive. I tried "something else" once, and it caused noise. The GM stuff never has. YMMV.
. I had a similar noise in my 88 30 years ago when I used a parts store 80W/90 that claimed it had the posi additive in it already. It squealed like a pig when turning in either direction. The tighter the turn, the louder the squeal. I pumped that lube out and refilled with GM axle lube and 1 tube of the additive from over the counter at my dealer. Prior to then, and every posi axle since, all I'll use is the GM lube with GM additive. I tried "something else" once, and it caused noise. The GM stuff never has. YMMV.
Melting Slicks
Joined: Nov 2016
Posts: 2,256
Likes: 3,082
From: So Cal
2023 C4 of the Year Finalist - Unmodified
I'm curious. Did you change the axle lube, and now the posi makes noise? What lube did you use that isn't working out?
Here are the GM long numbers for the lube and additive. These get a zillion hits in a search for purchase.
89021671 Axle lube.
88900330 Positraction additive.
I begin with one bottle of additive, and it is usually enough. If after a period of time the posi is still binding or jerking in turns, add another 4 oz. You probably won't have to. Cheers.
Here are the GM long numbers for the lube and additive. These get a zillion hits in a search for purchase.
89021671 Axle lube.
88900330 Positraction additive.
I begin with one bottle of additive, and it is usually enough. If after a period of time the posi is still binding or jerking in turns, add another 4 oz. You probably won't have to. Cheers.
Team Owner
Joined: Sep 2003
Posts: 25,393
Likes: 2,741
I'm curious. Did you change the axle lube, and now the posi makes noise? What lube did you use that isn't working out?
Here are the GM long numbers for the lube and additive. These get a zillion hits in a search for purchase.
89021671 Axle lube.
88900330 Positraction additive.
I begin with one bottle of additive, and it is usually enough. If after a period of time the posi is still binding or jerking in turns, add another 4 oz. You probably won't have to. Cheers.
Here are the GM long numbers for the lube and additive. These get a zillion hits in a search for purchase.
89021671 Axle lube.
88900330 Positraction additive.
I begin with one bottle of additive, and it is usually enough. If after a period of time the posi is still binding or jerking in turns, add another 4 oz. You probably won't have to. Cheers.
89021671 is same as ACD 10-4052
Mentioned ACD numbers to ease maybe comparison shopping. Single bottle is generally sufficient as mentioned.