Rear fluid capacity + additive
Thread Starter
Melting Slicks
Joined: Feb 2015
Posts: 2,069
Likes: 262
From: Park Ridge New Jersey
Rear fluid capacity + additive
yes I know I should've used the search function, but I did and it said 3.75 qts.
What I want to know about is the additive. I bought redline gear oil(75/90) and a bottle of additive.
1) do I need the additive with the redline lube?
2) how many bottles of additive(4 oz), I saw 2 bottles somewhere?
TIA
What I want to know about is the additive. I bought redline gear oil(75/90) and a bottle of additive.
1) do I need the additive with the redline lube?
2) how many bottles of additive(4 oz), I saw 2 bottles somewhere?
TIA
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 764
3.75 quarts seems to be a lot - ???
I could swear I saw 4 oz. additive somewhere, in either the 85 or 90 FSM. at this point, I wouldn't bet on it though. I recently serviced the differential in my 85. drained as much as I could get out, and pretty sure I got most of it using my transfer pump. I added 4 oz of additive, and approximately, 1.75 (1 qt.) bottles of gear oil. I used Castrol, limited slip, 80W90, filled to the plug. curiosities up - going to follow this thread. in the mean time, I'm going to check out my FSM's.
FWIW, I've only used one, 4 oz. bottle all the way back to my C3 days.
edit: I might add that the Castrol gear oil bottle, is stated as "limited slip," so I'm assuming it has some sort of additive. nowhere on the bottle does it say, do not add additive or additional additive not required. FWIW....
I could swear I saw 4 oz. additive somewhere, in either the 85 or 90 FSM. at this point, I wouldn't bet on it though. I recently serviced the differential in my 85. drained as much as I could get out, and pretty sure I got most of it using my transfer pump. I added 4 oz of additive, and approximately, 1.75 (1 qt.) bottles of gear oil. I used Castrol, limited slip, 80W90, filled to the plug. curiosities up - going to follow this thread. in the mean time, I'm going to check out my FSM's.
FWIW, I've only used one, 4 oz. bottle all the way back to my C3 days.
edit: I might add that the Castrol gear oil bottle, is stated as "limited slip," so I'm assuming it has some sort of additive. nowhere on the bottle does it say, do not add additive or additional additive not required. FWIW....
Last edited by Joe C; Jun 25, 2015 at 06:50 PM.
Team Owner
Joined: Sep 2003
Posts: 25,388
Likes: 2,741
yes I know I should've used the search function, but I did and it said 3.75 qts.
What I want to know about is the additive. I bought redline gear oil(75/90) and a bottle of additive.
1) do I need the additive with the redline lube?
2) how many bottles of additive(4 oz), I saw 2 bottles somewhere?
TIA
What I want to know about is the additive. I bought redline gear oil(75/90) and a bottle of additive.
1) do I need the additive with the redline lube?
2) how many bottles of additive(4 oz), I saw 2 bottles somewhere?
TIA
Where did you come up with the 3.75 QTS? Put the additive in FIRST and I believe you'll be hard pressed to do 1 1/2 QTS of the Red Line.
Post back with the amount you actually were able to get in until the fill plug seeped.
Is there a particular reason you chose the Red Line product?
Last edited by WVZR-1; Jun 25, 2015 at 06:32 PM.
Team Owner
Joined: Sep 2003
Posts: 20,179
Likes: 673
From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Thread Starter
Melting Slicks
Joined: Feb 2015
Posts: 2,069
Likes: 262
From: Park Ridge New Jersey
You need to determine if you'd like to use the additive OR NOT. What does the Red Line container say? Likely says NOT REQUIRED but many/most do and I'd think 1 sufficient. If you had no issues in tight turns with chatter I see no reason for MORE.
Where did you come up with the 3.75 QTS? Put the additive in FIRST and I believe you'll be hard pressed to do 1 1/2 QTS of the Red Line.
Post back with the amount you actually were able to get in until the fill plug seeped.
Is there a particular reason you chose the Red Line product?
Where did you come up with the 3.75 QTS? Put the additive in FIRST and I believe you'll be hard pressed to do 1 1/2 QTS of the Red Line.
Post back with the amount you actually were able to get in until the fill plug seeped.
Is there a particular reason you chose the Red Line product?
Redline, royal purple, mobile1....some of the best
This is where I found the 3.75 capacity and TWO bottles of additive (our very own Vader), but the empty rear looks like it will hold more than 1.5 qts.
http://temp.corvetteforum.net/c4/vader86/rearaxle.html
Team Owner
Joined: Sep 2003
Posts: 25,388
Likes: 2,741
Its a newly rebuilt unit and hasn't been on the car.
Redline, royal purple, mobile1....some of the best
This is where I found the 3.75 capacity and TWO bottles of additive (our very own Vader), but the empty rear looks like it will hold more than 1.5 qts.
http://temp.corvetteforum.net/c4/vader86/rearaxle.html
Redline, royal purple, mobile1....some of the best
This is where I found the 3.75 capacity and TWO bottles of additive (our very own Vader), but the empty rear looks like it will hold more than 1.5 qts.
http://temp.corvetteforum.net/c4/vader86/rearaxle.html
Perhaps the fill value is an error in pints vs. quarts but I'd think you'll find it will be substantially less than 2 Qts. Yours being a fresh build and a "dry" install is maybe more reason to have you post back with what you actually find for the fill value.
I don't believe you mentioned D44 or D36 so you might mention that also. For a "suction" to service I don't believe there would be a substantial difference in the fluid required BUT being a "fresh/dry" build it might interesting if you noted which.
Last edited by WVZR-1; Jun 26, 2015 at 10:13 AM.
Thread Starter
Melting Slicks
Joined: Feb 2015
Posts: 2,069
Likes: 262
From: Park Ridge New Jersey
Is the clutch pack fresh/new also or just bearings/seals. If the clutch pack were new there might be reason to maybe consider 2 additive especially if there's nothing noted on the Red Line container.
Perhaps the fill value is an error in pints vs. quarts but I'd think you'll find it will be substantially less than 2 Qts. Yours being a fresh build and a "dry" install is maybe more reason to have you post back with what you actually find for the fill value.
I don't believe you mentioned D44 or D36 so you might mention that also. For a "suction" to service I don't believe there would be a substantial difference in the fluid required BUT being a "fresh/dry" build it might interesting if you noted which.
Perhaps the fill value is an error in pints vs. quarts but I'd think you'll find it will be substantially less than 2 Qts. Yours being a fresh build and a "dry" install is maybe more reason to have you post back with what you actually find for the fill value.
I don't believe you mentioned D44 or D36 so you might mention that also. For a "suction" to service I don't believe there would be a substantial difference in the fluid required BUT being a "fresh/dry" build it might interesting if you noted which.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
Team Owner
Joined: Sep 2003
Posts: 20,179
Likes: 673
From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Geez. Just fill it up!
Last edited by JrRifleCoach; Jun 26, 2015 at 11:27 AM.
Team Owner
Joined: Sep 2003
Posts: 25,388
Likes: 2,741
That's what you do "FILL'R UP !!
In the car installation complete - if you assemble it out of the car you might want to do one quart plus the additive maybe and circulate it manually. Final fill is "in the car".
In the car installation complete - if you assemble it out of the car you might want to do one quart plus the additive maybe and circulate it manually. Final fill is "in the car".
Last edited by WVZR-1; Jun 26, 2015 at 11:31 AM.
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 764
per the 1985 FSM, section 0B-6, maintenance and lubrication, under limited-slip differential rear axle, IT STATES "...before filling, add 4 ounces of GM part number 1052358 or equivalent." as far as the 3.75 thing, WV may be right on the typo thing (pts vs. qts). 
w/ the above - just fill it up (to the plug level)!
there's probably a reason they sell this stuff in 4-oz bottles -
w/ the above - just fill it up (to the plug level)!there's probably a reason they sell this stuff in 4-oz bottles -
Race Director
Joined: Aug 2000
Posts: 11,470
Likes: 764
This is where I found the 3.75 capacity and TWO bottles of additive (our very own Vader), but the empty rear looks like it will hold more than 1.5 qts.
http://temp.corvetteforum.net/c4/vader86/rearaxle.html
http://temp.corvetteforum.net/c4/vader86/rearaxle.html
Description: Overhung pinion gear
Limited slip differential type: Standard, disc clutches
Drive pinion offset: 1.50" (8.5" ring gear), 1.125" (7.87" ring gear)
Drive pinion type: Hypoid
Number of differential pinions: Two
Pinion/Differential bearing adjustment: Shim
Driving wheel bearing: Tapered roller
Lubricant capacity: 3.75 pt
Lubricant type recommended: GL-5 gear lubricant
Lubricant SAE viscosity: 75W-90
it states pints NOT quarts. that capacity would make sense if it's total capacity - oil plus additive. I would still follow the FSM on the quantity of additive though.
Thread Starter
Melting Slicks
Joined: Feb 2015
Posts: 2,069
Likes: 262
From: Park Ridge New Jersey
Team Owner
Joined: Sep 2003
Posts: 20,179
Likes: 673
From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
