c3 differential fill plug
Thread Starter
Advanced
Joined: Jul 2013
Posts: 86
Likes: 0
From: Yukon OK
c3 differential fill plug
I tried the search and got back tons of info but still couldn't find the location of the fill plug. Also looked thru the AIM and saw nothing on the fill plug. Someone help a newb and direct me to it's location.
Drifting
Joined: Dec 2012
Posts: 1,360
Likes: 59
From: Meldrim Georgia
If you click on the link below you will see the ones with the red tag that's where mine is.
http://forums.corvetteforum.com/c3-g...it-or-not.html
http://forums.corvetteforum.com/c3-g...it-or-not.html
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
To break it loose, you may have to drop the spare tire and put a 4-foot pipe on a 1/2" square drive insert. If the last guy that had it out didn't put anti-seize on it, you're in for some real fun... 
Melting Slicks
Joined: Mar 2005
Posts: 2,093
Likes: 297
From: Midlothian VA
Try the photos in this thread
Last edited by Hammerhead Fred; Aug 13, 2013 at 09:39 PM.
Melting Slicks
Joined: May 2003
Posts: 3,030
Likes: 0
From: CFOT
Good luck OP. I wouldn't try and fiddle with it without removing the spare tire carrier. It will make your life much easier.
Thread Starter
Advanced
Joined: Jul 2013
Posts: 86
Likes: 0
From: Yukon OK
Changed the differential oil tonight. It was a breeze. I removed the spare tire carrier then took it to the car wash to remove some of the dirt/grease. I was able to break the the plug loose with a 6" cresent. Oil was pitch black but easy to remove and refill. Here's a few pics. Can anyone help ID the rear end by the number stamped on it? Thanks.
Rear end after the car wash
The fill plug
Stamped numbers
Rear end after the car wash
The fill plug
Stamped numbers
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Burning Brakes
Joined: Apr 2013
Posts: 926
Likes: 2
From: Castle Rock CO
I had to drop the spare tire and remove the lower housing to get it broke loose the first time. Took me about 1.5 hrs to suck the old fluid out and put new fluid in. Nice thing was after the spare tire housing was removed I did not need a pump to put the Mobil 1 LS Full Syn fliud in. I could just squeeze it in from the bottle and bottle feed it.
I did need a pump to suck it out and could remove 1.5 quarts from the rear diff which is a 2 quart fill.
Make sure you purchase the Limited Slip additive. GM has it but I used the most expensive after market product off the Local Parts Store along with 75w90 Mobil 1 LS Full Syn.
I did need a pump to suck it out and could remove 1.5 quarts from the rear diff which is a 2 quart fill.
Make sure you purchase the Limited Slip additive. GM has it but I used the most expensive after market product off the Local Parts Store along with 75w90 Mobil 1 LS Full Syn.