Rear Differential Lube
Acct Suspended APR 2026 by request
Joined: Dec 2010
Posts: 10,367
Likes: 1,272
2020 Corvette of the Year Finalist (performance mods)
C5 of Year Winner (performance mods) 2019
my opinion, amsoil severe gear 75/90... I have used that in my car since I bought it and never had a diff issue... amsoil torque drive atf in the trans as well also with good results... CCA has some pretty good deals on amsoil stuff
Burning Brakes
Joined: Feb 2013
Posts: 904
Likes: 296
From: Sacramento, California
Pro
Joined: Oct 2007
Posts: 607
Likes: 29
From: Tulsa Oklahoma
There is no "best". Use a quality synthetic gear lube with the appropriate amount of limited slip additive either already in the fluid or that you add yourself if you buy a non LS fluid.
I use Redline 75w-90.
I use Redline 75w-90.
Drifting
Joined: Sep 2017
Posts: 1,964
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From: Avon Lake OH
Team Owner
Joined: May 2001
Posts: 87,375
Likes: 1,593
From: Western NY
My '01 is a relatively low mileage car, but it's had RedLine fluids in the 6 speed and rear axle since 2002.......
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Melting Slicks
Joined: Aug 2014
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From: East Windsor NJ
Drifting
Joined: Dec 2000
Posts: 1,255
Likes: 50
From: Clayton, NC north carolina
for the rear diff..... any synthetic hypoid gear lube that you like....
for the trans GM synchromesh part # 88861800 per tremec. Most transmission guys will tell you the same... I took out the amsoil the previous owner of my Z06 had put in there and it shifts so much better... for the record even the Honda guys take out their factory fill and put in GM synchromesch.... GM really did well with this fluid.
The secret I believe lies in the friction modifier that GM puts in the oil it allows the friction material in the syncros to do its job.....
There is a reason why gm speed shops like spdc carry this stuff in stock... Strano of strano parts will tell you the same thing.
for the trans GM synchromesh part # 88861800 per tremec. Most transmission guys will tell you the same... I took out the amsoil the previous owner of my Z06 had put in there and it shifts so much better... for the record even the Honda guys take out their factory fill and put in GM synchromesch.... GM really did well with this fluid.
The secret I believe lies in the friction modifier that GM puts in the oil it allows the friction material in the syncros to do its job.....
There is a reason why gm speed shops like spdc carry this stuff in stock... Strano of strano parts will tell you the same thing.
Team Owner
Joined: Oct 1999
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From: Guinness Its whats for B'fast JAWGA
CI 3-4-5-9 Veteran
Le Mans Master
Joined: Apr 2012
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From: Brighton MI
Team Owner
Joined: Oct 1999
Posts: 31,977
Likes: 487
From: Guinness Its whats for B'fast JAWGA
CI 3-4-5-9 Veteran
David Farmer ran Mobil1 ATF in the trans during his time racing World Challenge, if it was good enough for him, it is good enough for me.
https://www.corvetteforum.com/forums...luid-poll.html
https://www.corvetteforum.com/forums...luid-poll.html
Last edited by 93Polo; Apr 10, 2018 at 12:14 PM.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
for the rear diff..... any synthetic hypoid gear lube that you like....
for the trans GM synchromesh part # 88861800 per tremec. Most transmission guys will tell you the same... I took out the amsoil the previous owner of my Z06 had put in there and it shifts so much better... for the record even the Honda guys take out their factory fill and put in GM synchromesch.... GM really did well with this fluid.
The secret I believe lies in the friction modifier that GM puts in the oil it allows the friction material in the syncros to do its job.....
There is a reason why gm speed shops like spdc carry this stuff in stock... Strano of strano parts will tell you the same thing.
for the trans GM synchromesh part # 88861800 per tremec. Most transmission guys will tell you the same... I took out the amsoil the previous owner of my Z06 had put in there and it shifts so much better... for the record even the Honda guys take out their factory fill and put in GM synchromesch.... GM really did well with this fluid.
The secret I believe lies in the friction modifier that GM puts in the oil it allows the friction material in the syncros to do its job.....
There is a reason why gm speed shops like spdc carry this stuff in stock... Strano of strano parts will tell you the same thing.
"This information applies to 2007 and prior GM passenger cars and trucks.
Dexron III is being phased out as a product name. It is being renamed Manual Transmission Fluid and carries p/n 88861800 U.S. (88861801 Canada).
If fluid p/n 88861800 U.S. (88861801 Canada) is not yet available when servicing a manual transmission or transfer case, Dexron III can be used in its place.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
Unavailability of manual transmission fluid part number 88861800 U.S. (88861801 Canada).
Recommendation/Instructions:
If fluid part number 88861800 U.S. (88861801 Canada) is unavailable when servicing a manual transmission or transfer case, Dexron III can be used in it's place. DO NOT use Dexron VI in place of the manual transmission fluid in any manual transmissions or transfer cases as a failure may result.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed."
Intermediate
Joined: May 2017
Posts: 29
Likes: 5
From: Houston Texas
I changed to Amsoil in the transmission and differential and definitely an improvement in the shift quality and I could assume the differential. I ran it all weekend at TX2K on drag radials roll racing as well as daily driving and still perfect so far.