Diff Whine
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Instructor
Joined: Nov 2024
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Diff Whine
Hi all - had the shop swap out my diff fluid to Amsoil severe gear 75-90 and tranny fluid to the Amsoil torque drive while getting the balancer replaced. Driving back from picking up the car and there seems to be a bit of a whine at highway speeds. Should I expect some type of "break-in" miles for this to go away? Prior to the change, there was no whine but I didn't have any records of prior changes so wanted to get a good baseline. When I did the initial research, looks like the severe gear has LS additives in it already. Wondering if I need to add some to correct the noise.
Melting Slicks
Joined: Dec 2018
Posts: 2,641
Likes: 1,377
From: Orange County, CA
After I rebuilt my diff with new clutch packs I filled it with Mobil 1 75-90 LS fluid. The diff would whine in turns a bit. Another forum member here mentioned that could happen, so I drained the Mobil 1 fluid and filled with AC Delco 10-4034 fluid. The noise went away!
Not saying this will be the fix for you, but there has been some documented history of LSD whine with fluid other than AC Delco.
Not saying this will be the fix for you, but there has been some documented history of LSD whine with fluid other than AC Delco.
Tech Contributor
Joined: Jan 2007
Posts: 19,360
Likes: 1,127
From: Dyer, IN
Hi all - had the shop swap out my diff fluid to Amsoil severe gear 75-90 and tranny fluid to the Amsoil torque drive while getting the balancer replaced. Driving back from picking up the car and there seems to be a bit of a whine at highway speeds. Should I expect some type of "break-in" miles for this to go away? Prior to the change, there was no whine but I didn't have any records of prior changes so wanted to get a good baseline. When I did the initial research, looks like the severe gear has LS additives in it already. Wondering if I need to add some to correct the noise.
Last edited by lucky131969; Jan 27, 2025 at 06:34 PM.
Drifting
Joined: Sep 2022
Posts: 1,350
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This is a 6-speed car, right?
How would you know it is the diff making the noise and not the trans?
Also, the friction modifier shouldn't have any effect on anything except when turning or burning, steady state cruise doesn't engage the diff clutches that the friction modifier is in there for.
How would you know it is the diff making the noise and not the trans?
Also, the friction modifier shouldn't have any effect on anything except when turning or burning, steady state cruise doesn't engage the diff clutches that the friction modifier is in there for.
Thread Starter
Instructor
Joined: Nov 2024
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Yes - 6 speed. Good point - I was just assuming its diff noise but could be from the transmission. I will say that other than the first time bringing the car back home this is the first time on the highway with it (bought it back in November). Its definitely not a loud noise but noticeable without the radio on. Not sure if a bit of noise is normal.
Pro
Joined: Dec 2014
Posts: 681
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From: Cincinnati Ohio
Yes - 6 speed. Good point - I was just assuming its diff noise but could be from the transmission. I will say that other than the first time bringing the car back home this is the first time on the highway with it (bought it back in November). Its definitely not a loud noise but noticeable without the radio on. Not sure if a bit of noise is normal.
