Question about friction Modifier
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Pro
Joined: Dec 2011
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From: North Reading MA
Question about friction Modifier
I am going to change my diff fluid tomorrow and the fluid I purchased says for limited slip. I also purchased a friction modifier.
Do I need it, and will it do any harm by adding it if the fluid is already setup for limited slip?
Do I need it, and will it do any harm by adding it if the fluid is already setup for limited slip?
Tech Contributor
Joined: Jan 2007
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From: Dyer, IN
My crystal ball seems to be broken. Can you disclose the fluid brand?
Thread Starter
Pro
Joined: Dec 2011
Posts: 718
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From: North Reading MA
Edit: Found my answer
"The Valvoline 75w90 meets the gm spec for differential service with NO additional additives needed"
Last edited by Mastertvtech; May 16, 2012 at 09:26 PM.
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From: King George VA
There is a downside to adding extra additive, so I think you made the right call. If the fluid is too "slippery" the diff clutch plates will have less friction than designed, thus your limited slip diff will be less limited slip (e.g. more open). While this will probably never be noticed on the street, in high performace applications like the drag strip or at the track, the tire with grip will get less torque in this condition. FYI, the diff spec is 75 ft-lbs thus the tire with grip should get that amount of torque with the rest just spinning the tire without grip. Too much slip and that number will go down.
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Use the lube as is out of the bottle. Do the recommended figure eights to properly lubricate the clutches with the new lube.
If,,,,,,,,,,,,,,,,,,,,,,, you get clutch chatter after the proper new fluid break in, you can add small amounts of modifier until it no longer chatters.
If,,,,,,,,,,,,,,,,,,,,,,, you get clutch chatter after the proper new fluid break in, you can add small amounts of modifier until it no longer chatters.
