Rear Differential Fluid
Thread Starter
Racer
Joined: Jul 2010
Posts: 391
Likes: 67
From: Oak Point Texas formerly okc
St. Jude Donor '16
Rear Differential Fluid
I bought a cheap 74 instead of hiring a therapist. Okay I got a therapist too. But I can't work on my 97 too much so I wanted an old one. It is L48 auto. My question is the rear differential. How do you change the fluid? Should I change the fluid? Should I even worry about it? Then what would you fill it with? It is shifting hard into reverse and thought I would start there. Thanks for all your help. I am a rookie with tools and that spells trouble.
Race Director
Joined: Apr 2011
Posts: 11,183
Likes: 3,335
From: North of Toronto - Ontario
Welcome 
Although I don't think changing the fluid will help the issue you describe, it's probably due for a change anyway
Here's a basic run down covering most of the problems with the fluid change
http://forums.corvetteforum.com/c3-t...ial-fluid.html
I'll add that when putting the new stuff in, if you use a tube on the end of the bottle lid, pin it in place so it doesn't end up inside the rear
M
Although I don't think changing the fluid will help the issue you describe, it's probably due for a change anyway
Here's a basic run down covering most of the problems with the fluid change
http://forums.corvetteforum.com/c3-t...ial-fluid.html
I'll add that when putting the new stuff in, if you use a tube on the end of the bottle lid, pin it in place so it doesn't end up inside the rear
M
Le Mans Master
Joined: Dec 2003
Posts: 5,381
Likes: 415
From: N J
When I did mine, I went the siphon route. Drove the car to heat it up first, then used a narrow tube attached to a squeeze bulb. This way took forever. Came out very slow, pretty thick stuff, but it worked.
At the time I didn't know any better, because what I thought was a bad rear end noise when going from park into reverse or drive, actually turned out to be worn u joints.
At the time I didn't know any better, because what I thought was a bad rear end noise when going from park into reverse or drive, actually turned out to be worn u joints.
Le Mans Master
Joined: Oct 2010
Posts: 6,930
Likes: 842
From: melbourne florida
2023 C3 of the Year Finalist - Modified
i bought a cheap fluid transfer pump for about 9 bucks at harbor freight and sucked out the old fluid , cleaned i and used it to refill it then pitched it. worked as well as anything
Burning Brakes
Joined: Oct 2001
Posts: 1,241
Likes: 4
From: Okinawa Okinawa
Thread Starter
Racer
Joined: Jul 2010
Posts: 391
Likes: 67
From: Oak Point Texas formerly okc
St. Jude Donor '16
I got this done in 1 hour. bought a hand pump from harbor freight and it made it easy. Thanks guys. The only issue was the new GM diff lube has the friction additive with it. It did not make a racket so I guess it is okay. Thanks for all your help. The pump is the way to go!!!!
