Rear Differential Drain
Thread Starter
Instructor
Joined: Jan 2008
Posts: 123
Likes: 0
From: Negaunee MI
Rear Differential Drain
Am i missing something or is there no drain plug for the rear diff on a 95 C4? I found the fill, And i don't want to take the axle out to change the fluid. Granted it does only have 34,000 for a 95 but i'm sure putting in fresh fluid can't hurt anything.
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
There is no drain. Some people have very carefully drilled and tapped it to add one. If you don't want to do that you can crack open the seal to drain it then hope you can put it back and it not leak. Finally the cheapest and least likely to cause trouble option is to suck the fluid out through the fill hole.
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 413
From: WV
There is no drain. Some people have very carefully drilled and tapped it to add one. If you don't want to do that you can crack open the seal to drain it then hope you can put it back and it not leak. Finally the cheapest and least likely to cause trouble option is to suck the fluid out through the fill hole.
...
...WW
Melting Slicks
Joined: Mar 2008
Posts: 2,351
Likes: 222
From: Delta B.C. Canada
2023 C7 of the Year Finalist - Unmodified
2019 C4 of Year Finalist (appearance mods)
2015 C4 of Year Finalist
Race Director
Joined: Jan 2012
Posts: 17,062
Likes: 166
From: United States
That oil doesnt need to be changed. My opinion. I recommend if you do change it get a Oil Analysis from Blackstone Labrotories and see what they say. i bet they say its almost new and is in perfect condition.
Melting Slicks
Joined: Mar 2008
Posts: 2,351
Likes: 222
From: Delta B.C. Canada
2023 C7 of the Year Finalist - Unmodified
2019 C4 of Year Finalist (appearance mods)
2015 C4 of Year Finalist
I bet the analysis would cost you more than fresh gear oil and posi additive.
Race Director
Joined: Dec 2002
Posts: 13,348
Likes: 233
From: SCMR Rat Pack'r Charter Member..Great Bend KS
Mine did, at about 60K miles. The clutch plates started moaning during tight turns. Replacing the diff lube cured it and it should be good to go for the duration.
Open diffs can go seemingly forever without a lube change. Limited-slip units, not so much.....
__________
not easily impressed....
Open diffs can go seemingly forever without a lube change. Limited-slip units, not so much.....
__________
not easily impressed....
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
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
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
Especially, if you do any kind of aggressive driving auto-x, track, 1/4 mile, etc...
Race Director
Joined: Jan 2012
Posts: 17,062
Likes: 166
From: United States
Mine did, at about 60K miles. The clutch plates started moaning during tight turns. Replacing the diff lube cured it and it should be good to go for the duration.
Open diffs can go seemingly forever without a lube change. Limited-slip units, not so much.....
__________
not easily impressed....
Open diffs can go seemingly forever without a lube change. Limited-slip units, not so much.....
__________
not easily impressed....
Regardless, changing oil just because you feel it is bad is wasteful. Have a sample tested, for 25 bucks. They will tell you the condition of the oil and contaminants within the oil.
But if people just want to change oil to change oil, its your money. If you dont know if something is worn with the oil, or within the parts, you are just wasting money in the long run. Its my opinion, nothing more.
I would be more concerned of 17 year old antifreeze and brake fluid, than my differential fluid.
Last edited by krackenvette; Mar 19, 2012 at 09:13 PM.
Thread Starter
Instructor
Joined: Jan 2008
Posts: 123
Likes: 0
From: Negaunee MI
I did replace the antifreeze and the trans fluid this weekend and the brake fluid was about 3 years ago. Once i new it wasn't a simple drain and fill i decided not to mess with the diff. Thanks for all the help guys and gals!!!
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Race Director
Joined: Jan 2012
Posts: 17,062
Likes: 166
From: United States
Safety Car
Joined: Jun 2006
Posts: 3,629
Likes: 28
From: FL
For what it is worth I will point out that Chrysler specified a 12,000 mile change interval for differential lube on Viper which used a nearly identical D44. Yes, that might be overkill, but as others point out changing lubricant is cheap insurance.
See my post #4 in this link for the procedure to install what GM forgot on the C4.
http://forums.corvetteforum.com/c4-t...questions.html
See my post #4 in this link for the procedure to install what GM forgot on the C4.
http://forums.corvetteforum.com/c4-t...questions.html
Thread Starter
Instructor
Joined: Jan 2008
Posts: 123
Likes: 0
From: Negaunee MI
For what it is worth I will point out that Chrysler specified a 12,000 mile change interval for differential lube on Viper which used a nearly identical D44. Yes, that might be overkill, but as others point out changing lubricant is cheap insurance.
See my post #4 in this link for the procedure to install what GM forgot on the C4.
http://forums.corvetteforum.com/c4-t...questions.html
See my post #4 in this link for the procedure to install what GM forgot on the C4.
http://forums.corvetteforum.com/c4-t...questions.html
Awesome thank you this helps a lot.
Instructor
Joined: Jul 2011
Posts: 204
Likes: 10
From: Meridianville, Alabama
Race Director
Joined: May 2001
Posts: 14,165
Likes: 9
It's just called cheap insurance. I just changed the oil in my dad's 1946 Chevy pickup, it only had 900 miles on it, but it was 5 years old. Call me crazy but I'll spend the $20 to change it just in case there were contaminants in the old oil that might cost an engine. Back on the subject of the differential, consider worst case $100. If you're not willing to spend $100 every 17 years, maybe you shouldn't own a Corvette, or any car for that matter.
Race Director
Joined: Nov 2003
Posts: 12,221
Likes: 446
From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Le Mans Master
Joined: Oct 2008
Posts: 9,758
Likes: 49
From: Houston Texas
Did you have an oil analysis done? There is the oil and the gm additive. I bet the additive wore out.
Regardless, changing oil just because you feel it is bad is wasteful. Have a sample tested, for 25 bucks. They will tell you the condition of the oil and contaminants within the oil.
But if people just want to change oil to change oil, its your money. If you dont know if something is worn with the oil, or within the parts, you are just wasting money in the long run. Its my opinion, nothing more.
I would be more concerned of 17 year old antifreeze and brake fluid, than my differential fluid.
Regardless, changing oil just because you feel it is bad is wasteful. Have a sample tested, for 25 bucks. They will tell you the condition of the oil and contaminants within the oil.
But if people just want to change oil to change oil, its your money. If you dont know if something is worn with the oil, or within the parts, you are just wasting money in the long run. Its my opinion, nothing more.
I would be more concerned of 17 year old antifreeze and brake fluid, than my differential fluid.
To the OP please change your oil you will feel better about it and so will I.
Race Director
Joined: Jan 2012
Posts: 17,062
Likes: 166
From: United States
I guess we aren't as smart *** you. But the point should be taken that after 17 years someone decides to change diff oil. And 34,000 miles. Time vs actual use. Regardless, we all have our advice, and opinions. Its a forum, not an ASE certified mechanics thread. Its just that, nothing more.