Fluid change - differential
Le Mans Master
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From: Akron Ohio
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St. Jude Donor '09-'10-'11
I want to say mine is a 3/8" or 10mm allen. I know it is not as big as the transmission.
Le Mans Master
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From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
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St. Jude Donor '09-'10-'11
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Instructor
Joined: Jan 2007
Posts: 112
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From: Belleville Wisconsin
How often should the differential fluid be changed? How much fluid does it hold? Do you need to siphon it out to get it all? What would a quality replacement fluid be? Maybe I should do mine this spring as well(1992 ; 89K).
Safety Car
Joined: Jul 2008
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From: Made In America
St. Jude Donor '10-'11
IIRC, GM has a special differential fluid and additive that goes in it.
Last edited by M.J.L.; Mar 13, 2009 at 12:40 PM.
Safety Car
Joined: Jul 2008
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From: Made In America
St. Jude Donor '10-'11
Le Mans Master
Joined: Oct 2007
Posts: 9,700
Likes: 3,469
From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
2024 C5 of the Year Winner - Modified
2023 C5 of the Year Finalist - Modified
2022 C5 of the Year Finalist - Modified
St. Jude Donor '09-'10-'11
I did not siphon mine out the first time. I drilled a 7/16" hole in the bottom just to the side of the bottom bolt. I then tapped it with a 1/4-18 NPT pipe tap and pluged it. Now it all just drains out and then I refill. Takes 15 min. tops.
Le Mans Master
Joined: Oct 2007
Posts: 9,700
Likes: 3,469
From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
2024 C5 of the Year Winner - Modified
2023 C5 of the Year Finalist - Modified
2022 C5 of the Year Finalist - Modified
St. Jude Donor '09-'10-'11
Was it this one?
http://forums.corvetteforum.com/c4-t...ne-search.html
This is not my diff but the hole I put in mine is right where this guy put his. I went with the recessed allen plug right off the bat. The square head will definitely not clear the exhaust.
Safety Car
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From: MANDEVILLE, LA La
Dear CAJUN C4,
toptechx6 has just replied to a thread you have subscribed to entitled - Rear End Drain Plug Pictures? - in the C4 Technical and Performance forum of Corvette Action Center.
This thread is located at:
http://www.corvetteactioncenter.com/...-new-post.html
Here is the message that has just been posted:
***************
Inside
Image: http://i84.photobucket.com/albums/k3...0098Medium.jpg
Outside
Image: http://i84.photobucket.com/albums/k3..._1065Large.jpg
You need a 5/16” drill bit, a 1/8 X 27 pipe tap and a plug the same size. Center punch a spot 1/2 inch left of the lowest bolt centerline and 1/2 inch forward of the batwing cover. Use care when drilling to avoid nicking the ring gear, a depth "stop" on your drill at about 1 inch will work. (Slide a length of rubber tubing on the drill bit cut to the correct length.)
If you are installing the drain plug with the differential in the car it helps to have a long 5/16” drill bit, use a ¼ drive 12 point socket with extension to turn the tap. The draining lubricant will remove any chips.
toptechx6 has just replied to a thread you have subscribed to entitled - Rear End Drain Plug Pictures? - in the C4 Technical and Performance forum of Corvette Action Center.
This thread is located at:
http://www.corvetteactioncenter.com/...-new-post.html
Here is the message that has just been posted:
***************
Inside
Image: http://i84.photobucket.com/albums/k3...0098Medium.jpg
Outside
Image: http://i84.photobucket.com/albums/k3..._1065Large.jpg
You need a 5/16” drill bit, a 1/8 X 27 pipe tap and a plug the same size. Center punch a spot 1/2 inch left of the lowest bolt centerline and 1/2 inch forward of the batwing cover. Use care when drilling to avoid nicking the ring gear, a depth "stop" on your drill at about 1 inch will work. (Slide a length of rubber tubing on the drill bit cut to the correct length.)
If you are installing the drain plug with the differential in the car it helps to have a long 5/16” drill bit, use a ¼ drive 12 point socket with extension to turn the tap. The draining lubricant will remove any chips.
