rear diff. question...'73
Thread Starter
Racer
Joined: Oct 2005
Posts: 469
Likes: 0
From: West Slope of the Sierras California
rear diff. question...'73
OK, first time 'Vette owner here, hence the name, is there a drain plug on these diffs. or do you have to pump the old fluid out? Looked under there for half an hour and saw nothing that resembled a drain plug.
Thanks........R
Thanks........R
Safety Car
Joined: Jun 2004
Posts: 4,652
Likes: 80
From: Lakeland Florida
There may not be a drain plug in the diff unless a previous owner put one in. You have to buy a hand pump, insert the hose into the plug opening, and pump out all the old oil.
It may make the job easier to remove the spare tire carrier from under the car. Once the car is up on jacks, ( checked for safety ) you will have enough room to do this job.
I forgot the type of rear oil that is used, but its somewhere around 90w. One of the items that you need to get is anti slip additive. You can get the original brand name, or an additive at a parts store. This additive needs to go in the emply diff first, then pump the new oil into it untill it starts to come out of the drain hole. Why put the new stuff in first? Becasue once its full of the new oil, there is no room to put the new additive.
The factory manual says that after the oil is replaced to find an area and make several tight figure 8s to lubricate the gears correctly. If you cannot find an area to do figure 8s, then about 25 miles of driving may accomplish the same task.
kdf
It may make the job easier to remove the spare tire carrier from under the car. Once the car is up on jacks, ( checked for safety ) you will have enough room to do this job.
I forgot the type of rear oil that is used, but its somewhere around 90w. One of the items that you need to get is anti slip additive. You can get the original brand name, or an additive at a parts store. This additive needs to go in the emply diff first, then pump the new oil into it untill it starts to come out of the drain hole. Why put the new stuff in first? Becasue once its full of the new oil, there is no room to put the new additive.
The factory manual says that after the oil is replaced to find an area and make several tight figure 8s to lubricate the gears correctly. If you cannot find an area to do figure 8s, then about 25 miles of driving may accomplish the same task.
kdf
Pro
Joined: Apr 2000
Posts: 625
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From: The Villages FL
Rear Diff Drain Plug
The Corvette Clinic sells drain kits for less than $50 through Ecklers and Corvette Central. That will solve your problem in the future. If you can't find one in a catalog, let me know and I'll forward your request. When the daily repair shop was open, practically every Corvette that may come back as repeat business got one installed on the first visit.
Spike
Spike
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Drifting
Joined: Nov 2002
Posts: 1,951
Likes: 1
From: Shore NJ
You'll need the posi-additive which is sold at any Chevy dealer, I've actually seen it also at the local Pep Boys here. As far as a drainage kit goes sounds like you found the drain plug and tag so go to a local surgical supply house and get the largest syrinige they sell, trim the end of the syrinige so the end is larger and get a short piece of clear hose, just remove the old fluid out and your good to go. I would remove the tire carrier to make it easier....
Last edited by 73jst4fun; Nov 13, 2005 at 09:16 PM.
Safety Car
Joined: Jun 2004
Posts: 4,652
Likes: 80
From: Lakeland Florida
I bought a hand pump at the parts store. It helped to get this stuff out. There was no way to get it to siphon, and the smell of the old oil was pretty rancid. The pump was similar to a syringe about the size of a coke bottle. Pull out to siphon and push down to pump it into a drainage container.
kdf
kdf
Safety Car
Joined: Jun 2002
Posts: 4,135
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i remember seeing a article about a drain plug kit,,,the kit included the proper bit and tap and drain plug ,,plus a template,,you drilled the hole tapped it and the old oil flows out cleaning the metal filings,,dope up the new plug ,,fill and good to go