Rear axle fluid change- process ?
Thread Starter
Racer
Joined: Nov 2001
Posts: 392
Likes: 6
From: Churchville PA
Rear axle fluid change- process ?
Does anyone have a quick write up from fsm or general instructions around swapping the diff fluid? Anything different needs to be done on my '80 than any other vehicle? I usually pull the diff cover, wipe out as much of the fluid as I can, spray it down with Brake Kleen real good, replace diff cover with orange RTV and then refill with diff fluid.
What's the best weight oil to use?
And of course, I'll put the 4oz of GM additive before the diff fluid... and run a few figure 8's when it's all done.
What's the best weight oil to use?
And of course, I'll put the 4oz of GM additive before the diff fluid... and run a few figure 8's when it's all done.
Le Mans Master
Joined: Jan 2004
Posts: 7,412
Likes: 75
St. Jude Donor '14
You have to drop the diff out to remove the cover. Most people simply suck out the old, put in the new with the additive. I had the quicky lube suck it out and refill it with the stuff I bought. I felt they would get more of the old stuff out than I could. The plug is a bit of a pain to access but it can be done.
mike
mike
Burning Brakes
Joined: Jan 2006
Posts: 957
Likes: 6
From: Burlington wisconsin
Crude, but I taped / rigged up a hose to my shop vac, moved the hose around in the diff as much as humanly possible & sucked it all out. You can't clean it like we'd all like to with out dropping the diff. Just remember to take the filter out of the wet vac first or you'll wreck the filter.
Jimbo
Jimbo
Race Director
Joined: Sep 2001
Posts: 10,560
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From: Wellington, FL
St. Jude Donor '11 thru '25
IMO, the best way is to drill, tap, and then use a drain plug. This method makes it a breeze for your next change, and gets practically all the fluid drained. In addition to the GM additive, I use Mobil 1 synthetic.
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Verdad Gallardo
Team Owner
Joined: Aug 2006
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From: Columbia Missouri
Race Director
Joined: Sep 2001
Posts: 10,560
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From: Wellington, FL
St. Jude Donor '11 thru '25
Actually, I must admit I didn't do it. I took it to a shop that worked on nothing but Vettes and told them I wanted the rear fluid changed. (This was probably in 1978 or so.) And, long story short, that's the way they did that particular job. They just drilled a hole, let the fluid run out, tapped the hole, inserted a drain plug, and filled 'er up. The draining fluid removes any shavings. I changed it several times since and it's a breeze to do as you don't have to screw around sucking the old fluid out. Also, this way you can get it all out.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Actually, I must admit I didn't do it. I took it to a shop that worked on nothing but Vettes and told them I wanted the rear fluid changed. (This was probably in 1978 or so.) And, long story short, that's the way they did that particular job. They just drilled a hole, let the fluid run out, tapped the hole, inserted a drain plug, and filled 'er up. The draining fluid removes any shavings. I changed it several times since and it's a breeze to do as you don't have to screw around sucking the old fluid out. Also, this way you can get it all out.
Sweet...new project idea.
Race Director
Joined: Sep 2001
Posts: 10,560
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From: Wellington, FL
St. Jude Donor '11 thru '25
Team Owner
Joined: Aug 2006
Posts: 24,125
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From: Columbia Missouri
Racer
Joined: Aug 2005
Posts: 431
Likes: 0
From: Oita, Japan
I drilled a hole and used an 1/8" NPT tap and put a plug in there. If you can find a magnetic plug, use that. I did this with the differential out of the car but as others have said, you should be able to do it in the car as well.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Great pic. Is that the lowest part of the diff? Looks terrific.