Not engine mod but rear gear question.
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Le Mans Master
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From: The problem is all inside your head she said to me.
Not engine mod but rear gear question.
The car we bought on Saturday is supposed to have a just put in 8.5 auburn posi. It made a hell of a wracheting sound when we picked it up. The guy said the shop said it will break in in 500 miles. This guy put synthic(sp) gear lube in it. It was better buy the time we drove it 2.5 hour home. but it is still doing it. I guess the odometer on the new electric speedo says about 380miles now. Is this normal??? Should I put dino oil in during the breank in????????
Race Director
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Re: Not engine mod but rear gear question. (INMYBLOOD)
What was the actual brand and type of oil? Does it include the friction modifiier? If not was any installed with the oil?
Auburn cone type limited slip diffs need the friction modifier just as the clutch type units need it.
duke
Auburn cone type limited slip diffs need the friction modifier just as the clutch type units need it.
duke
Thread Starter
Le Mans Master
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From: The problem is all inside your head she said to me.
Re: Not engine mod but rear gear question. (SWCDuke)
Duke I don't know if a friction modifier was added? I could call him or change the oil. But should it or should it not make any noise if brand new??????? Thanks for any help.
Drifting
Joined: Jun 2002
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From: Orlando Florida
Re: Not engine mod but rear gear question. (INMYBLOOD)
Try using GM posi-traction additive. It can be purchased at your local Chevrolet dealer.
It should clear up your noise. Redline lubricants also makes a great rear end oil. :conehead
It should clear up your noise. Redline lubricants also makes a great rear end oil. :conehead
Race Director
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Re: Not engine mod but rear gear question. (INMYBLOOD)
If it doesn't have the friction modifier, it will probably chatter - new or used. Do whatever you have to do to ensure that the friction modifier is installed.
I use the GM axle oil and fiction modifier because I KNOW IT WORKS. Redline makes two different 75W-90 GL-5 axle oils. One has no friction modifier and the other has it. I've been told by others that their friction modified gear oil works fine with clutch or cone type limited slips.
You could ask the guy who did the install what kind of oil he used - whether or not it had the friction modifier, or whether he added any if it did not, but you know how that goes - you'll be lucky to get a straight and honest answer. A mechanic will rarely admit that he might have screwed up. You just get the runaround and a bunch of BS!
If you have a copy of the original RO it should state what type of materials he used if there was a specific charge for them.
Duke
[Modified by SWCDuke, 10:46 PM 6/26/2002]
I use the GM axle oil and fiction modifier because I KNOW IT WORKS. Redline makes two different 75W-90 GL-5 axle oils. One has no friction modifier and the other has it. I've been told by others that their friction modified gear oil works fine with clutch or cone type limited slips.
You could ask the guy who did the install what kind of oil he used - whether or not it had the friction modifier, or whether he added any if it did not, but you know how that goes - you'll be lucky to get a straight and honest answer. A mechanic will rarely admit that he might have screwed up. You just get the runaround and a bunch of BS!
If you have a copy of the original RO it should state what type of materials he used if there was a specific charge for them.
Duke
[Modified by SWCDuke, 10:46 PM 6/26/2002]
Thread Starter
Le Mans Master
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From: The problem is all inside your head she said to me.
Re: Not engine mod but rear gear question. (SWCDuke)
Can I put the Gm additive in with the synthetic oil?? I guess it would not hurt to be sure. But one part of my question was will a new one make noise?
Race Director
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Re: Not engine mod but rear gear question. (INMYBLOOD)
A new positraction unit should NOT make noise as long as the friction modifier is added with the new gear oil.
As far as I know synthetics use the same friction modifier as mineral based gear oils, and as far as I know the friction modifier sold by GM, Ford, Mercedes, etc, is the basically the same stuff.
You might want to contact Auburn as ask them for their recommendations on both gear oil and friction modifer. When in doubt, read the instructions (did any come with the unit) or contact the manufacturer.
As an interesting historical footnote, the friction modifier use to be referred to as "whale sperm", probably because it actually was a whale oil product and/or because the price is so high. In addition to being used as a friction modifier for limited slip diffs back in the fifties and sixties, it was an addititive in the old Type "A" ATF. It performed the same function in both automatic transmissions and positraction axles - prevented chattering of the wet clutches.
Whale oil products were outlawed for sale in the US back in the seventies, so they had to find a substitute for the whale oil, but I don't know what it is.
Duke
Duke
As far as I know synthetics use the same friction modifier as mineral based gear oils, and as far as I know the friction modifier sold by GM, Ford, Mercedes, etc, is the basically the same stuff.
You might want to contact Auburn as ask them for their recommendations on both gear oil and friction modifer. When in doubt, read the instructions (did any come with the unit) or contact the manufacturer.
As an interesting historical footnote, the friction modifier use to be referred to as "whale sperm", probably because it actually was a whale oil product and/or because the price is so high. In addition to being used as a friction modifier for limited slip diffs back in the fifties and sixties, it was an addititive in the old Type "A" ATF. It performed the same function in both automatic transmissions and positraction axles - prevented chattering of the wet clutches.
Whale oil products were outlawed for sale in the US back in the seventies, so they had to find a substitute for the whale oil, but I don't know what it is.
Duke
Duke
Thread Starter
Le Mans Master
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From: The problem is all inside your head she said to me.
Re: Not engine mod but rear gear question. (SWCDuke)
Thanks Duke my plan is to drain the synthetic and replace it with GM lube and additive ASAP. Thanks.
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Thread Starter
Le Mans Master
Joined: Feb 2001
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From: The problem is all inside your head she said to me.
Re: Not engine mod but rear gear question. (INMYBLOOD)
Update
Duke I drained the synthetic out and put regular dyno oil and additive and it's fixed. :D I hope it did not get damaged in the time we drove it? It was making quite a racket :eek:
Duke I drained the synthetic out and put regular dyno oil and additive and it's fixed. :D I hope it did not get damaged in the time we drove it? It was making quite a racket :eek:
Race Director
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Re: Not engine mod but rear gear question. (INMYBLOOD)
I doubt if any permanent damage was done, and I'm glad it worked out. It's amazing how many professionals are clueless about the lubrication requirements of limited slip diffs.
Duke
Duke