What oil do I use in rear diff?
Thread Starter
Safety Car
Joined: Mar 2000
Posts: 4,078
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From: Northeast South Dakota
What oil do I use in rear diff?
I am going to be changing the oil in my rear diff. I know I need 24 oz. of gear lube and 4 oz. of posi additive, but what wt. do I use for gear lube? Is it just SAE 90 or what? And, is posi additive something that is made by a number of companies, or do I have to get GM? My Chilton's manual (worthless) says I need GM part no. xxxxx. :rolleyes: Now what good does that kind of information do me? I don't know why it doesn't say what kind of oil it's supposed to have. :cheers:
Le Mans Master
Joined: Aug 2000
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From: Semper ubi, sub ubi
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Re: What oil do I use in rear diff? (Dalannex)
I'd use GM rearend lube, you can get it from any GM dealer it only cost about $4.00 for qt. Also only use GM positract additive, don't go with the stuff they sell at parts stores.
Drifting
Joined: Mar 2000
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From: Haysville Ks
Re: What oil do I use in rear diff? (Dalannex)
Stay with the GM lube. There are two different part # for the rear end lube. I know my 4gen Camaro's use a different lube than the Vette, same posi additive. Check with your local GM parts man for the correct lube.
Melting Slicks
Joined: May 1999
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From: Moon Township PA
Re: What oil do I use in rear diff? (Dalannex)
Only two choices in my book: GM brand rear lube or Mobil 1 synthetic gear lube. Either one gets two bottles of GM brand positraction additive. BTW, I prefer the Mobil 1.
Gary
Gary
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Safety Car
Joined: Mar 2000
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From: Northeast South Dakota
Re: What oil do I use in rear diff? (GaryS)
I was afraid you would all say that. Now I have to go to my local GM dealer and have them order the stuff. (They really suck!! They don't stock anything :mad ) I suppose I could go for a 60 mile drive, but I kind of hate to do that for a couple of quarts of lube. Oh well, guess I'll do this job next week. :rolleyes: :) Of course, I need to go to "the other" GM dealer anyway, my local dealer told me they don't show the battery connector on the distributor on my vette, and that it must be discontinued. You know the one, it's white plastic, single spade terminal, all GM's with distributors have them and they all have the tab that locks them on broke off, but the local chevy dealer doesn't know anything about it.
-Justin
-Justin
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Joined: Nov 2000
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From: Racine, WI USA
Re: What oil do I use in rear diff? (Dalannex)
I have a 1973 that had original fluid in it. When I rebuild the differential, I replaced the fluid with new GM fluid. After long trips the posi clutches "dried out." People told me the "new" fluid is not as good as the old fluid. I drained the differential and replaced it with Red Line and a bottle of posi fluid. No problems for at least a year now.
Team Owner
Joined: Aug 1999
Posts: 28,722
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From: Fort Mill, SC via NJ
Re: What oil do I use in rear diff? (ken welch)
I have a 1973 that had original fluid in it. When I rebuild the differential, I replaced the fluid with new GM fluid. After long trips the posi clutches "dried out." People told me the "new" fluid is not as good as the old fluid. I drained the differential and replaced it with Red Line and a bottle of posi fluid. No problems for at least a year now.
Went to Amsoil synthetic rear fluid and problem went away immediately.
I now use synthetic in the engine,th400(in a couple of weeks) and rear.
I was told the new posi clutch packs are different along with since the GM posi additive isn't whale oil anymore it isn't as good.
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Thread Starter
Safety Car
Joined: Mar 2000
Posts: 4,078
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From: Northeast South Dakota
Re: What oil do I use in rear diff? (69er)
I changed the oil today. The local Chevy dealer happened to have the posi additive. He said the reason they have it is that the local John Deere shop buys the stuff from them by the case to use in some piece of equipment or another. Of course, they didn't have oil, so I had to get that at the parts store. Anyway, it's done now, so mark that one off the list. :D
Drifting
Joined: Jan 2002
Posts: 1,645
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From: Schaumburg IL
Re: What oil do I use in rear diff? (Dalannex)
A good quality like Valvoline 90wt lube is what ok. 2 quarts is what the rear holds. This is from a rear end reuilding shop. However, they said STICK WITH THE GM POSI LUBE.
