Changing Gear Lube on C3
Thread Starter
Advanced
Joined: Apr 2008
Posts: 67
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From: Wilmington DE
Changing Gear Lube on C3
Have a 1970 and think it is time to change the gear lube.
Does anyone know the right gear lube to use?
Use Mobil 1 75W90 synthetic only.
or
Use one bottle of GM positraction additive and two bottles of GM rear axle lube.
Regards,
Rich
Does anyone know the right gear lube to use?
Use Mobil 1 75W90 synthetic only.
or
Use one bottle of GM positraction additive and two bottles of GM rear axle lube.
Regards,
Rich
Advanced
Joined: Jun 2004
Posts: 93
Likes: 0
From: Southgate MI
This is what you need. i don't know about the price.
http://www.ecklers.com/product.asp?p...8&dept_id=1872
Tom1701
http://www.ecklers.com/product.asp?p...8&dept_id=1872
Tom1701
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
Instead of removing the cover (pain), pump out the old stuff.
Use something like this:
http://www.summitracing.com/parts/WMR-W1145/
Agree with Tom,..use the recommended conventional 80w-90 lube and 4 oz. bottle of GM friction modifier.
Use something like this:
http://www.summitracing.com/parts/WMR-W1145/
Agree with Tom,..use the recommended conventional 80w-90 lube and 4 oz. bottle of GM friction modifier.
Last edited by 73, Dark Blue 454; May 10, 2010 at 05:02 PM.
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Team Owner
Joined: Mar 2002
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See the "LS" on that bottle? No additive needed
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
Pour whatever you want into your differential. Just be aware, that:
Strange Engineering (who builds 1000's of rear ends),
Moser Engineering (who builds 1000's of rear ends),
Tom's Differentials (who builds 1000's of rear ends),
Auburn (who also makes a fine LS carrrier),
Dana (who makes makes a fine LS carrier for newer Vettes for instance),
And Eaton themselves, the company that designed and manufactures the LS carrier installed in your C3,
...ALL recommend against the use of synthetics with their limited slip carriers. They all recommend conventional lube with the GM friction modifier.
Strange Engineering (who builds 1000's of rear ends),
Moser Engineering (who builds 1000's of rear ends),
Tom's Differentials (who builds 1000's of rear ends),
Auburn (who also makes a fine LS carrrier),
Dana (who makes makes a fine LS carrier for newer Vettes for instance),
And Eaton themselves, the company that designed and manufactures the LS carrier installed in your C3,
...ALL recommend against the use of synthetics with their limited slip carriers. They all recommend conventional lube with the GM friction modifier.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
I've used mostly all GM for years (but 2 bottles of additive)with good results and have used other mixtures (GM additive)that were recommended by whoever rebuilt the rearend with good results also.
I'll have to try the Mobile 1 LS on some problem rearends and see how it does.
Melting Slicks
Joined: Mar 2005
Posts: 2,838
Likes: 10
From: Austin TX
http://www.eaton.com/EatonCom/Produc.../FAQ/CT_128414
...is this:
(scroll down to the Eaton Posi section)
"What kind of oil should I use? Can I use synthetics? Do I need a friction additive/modifier?
Eaton Posi units perform best when using GL4 (or better) mineral/petroleum based gear oil. A four ounce bottle of friction additive/modifier is also necessary for optimum performance."
From here:
http://www2.dana.com/pdf/5323.pdf
...is this:
"Limited slip differentials impose additional requirements on lubricants,.. Some otherwise good lubricants do not preclude "chatter" or "bumping" in turning corners with Limited Slip Differentials. Many vehicle manufacturers find it necessary to specify a special lubricant or lubricant additive for use with Limited Slip Differentials. Check the vehicle manufacturer's lubricant recommendations".
From here:
http://www.auburngear.com/aftermarke...6pagesize%3d20
...is this:
(click on Limited Slip Differential Install Instructions)
...is this:
"The Auburn Gear limited-slip differential design has been extensively tested with high quality non-synthetic 80W90 hypoid oils treated with GM or Ford friction additives (3 oz. of additive will treat 1 quart of oil). To avoid differential clutch chatter (noise) and for optimum performance, use the oil and additive described above. Use of other additive and oil types may cause differential clutch chatter.
Ford Part Number: C8A219B546A
GM Part Number: 1052358"
To verify lube recommendations from those I cited who build differentials, please call:
Tom's Differentials (an Eaton dealer),..208-265-8111
Strange Engineering (another Eaton dealer)...847-663-1701
Moser Engineering (another Eaton dealer)...260-726-6689
Last edited by 73, Dark Blue 454; May 11, 2010 at 12:18 PM.
Team Owner
Joined: Mar 2002
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Dang I just learned something new today. I've never seen the LS before is this new ?
I've used mostly all GM for years (but 2 bottles of additive)with good results and have used other mixtures (GM additive)that were recommended by whoever rebuilt the rearend with good results also.
I'll have to try the Mobile 1 LS on some problem rearends and see how it does.
I've used mostly all GM for years (but 2 bottles of additive)with good results and have used other mixtures (GM additive)that were recommended by whoever rebuilt the rearend with good results also.
I'll have to try the Mobile 1 LS on some problem rearends and see how it does.
Thread Starter
Advanced
Joined: Apr 2008
Posts: 67
Likes: 0
From: Wilmington DE
I checked the price of the GM gear oil GM #89021671 the price is $16.84 for 23 ounces.
The posi additive is $12.54 for 4 ounces.
I cannot believe what GM charges for gear oil. Also, 23 ounces is not a full quart. I may need to purchase 3 containers of the 23 ounce stuff + posi additive.
$63.00 for gear lube, is it me or is this just a total rip off.?
I appreciate the information about using GM only lubricants, but if this is what it costs, I would really like to know the following: Why are synthetics not good, What is the real problems they cause?
The posi additive is $12.54 for 4 ounces.
I cannot believe what GM charges for gear oil. Also, 23 ounces is not a full quart. I may need to purchase 3 containers of the 23 ounce stuff + posi additive.
$63.00 for gear lube, is it me or is this just a total rip off.?
I appreciate the information about using GM only lubricants, but if this is what it costs, I would really like to know the following: Why are synthetics not good, What is the real problems they cause?
Safety Car
Joined: Mar 2009
Posts: 3,558
Likes: 4
From: Oakland California
Dang I just learned something new today. I've never seen the LS before is this new ?
I've used mostly all GM for years (but 2 bottles of additive)with good results and have used other mixtures (GM additive)that were recommended by whoever rebuilt the rearend with good results also.
I'll have to try the Mobile 1 LS on some problem rearends and see how it does.
I've used mostly all GM for years (but 2 bottles of additive)with good results and have used other mixtures (GM additive)that were recommended by whoever rebuilt the rearend with good results also.
I'll have to try the Mobile 1 LS on some problem rearends and see how it does.
.
Burning Brakes
Joined: Sep 2008
Posts: 805
Likes: 5
From: Naperville Illinois
I used the heavier weight Lucas gear oil and Trans-X. The bottle says it meets OEM specs for GM Ford & Chysler. My posi has performed flawlessly and is very quiet.
Premium Supporting Vendor
Joined: Aug 2001
Posts: 5,364
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From: King George VA
I checked the price of the GM gear oil GM #89021671 the price is $16.84 for 23 ounces.
The posi additive is $12.54 for 4 ounces.
I cannot believe what GM charges for gear oil. Also, 23 ounces is not a full quart. I may need to purchase 3 containers of the 23 ounce stuff + posi additive.
$63.00 for gear lube, is it me or is this just a total rip off.?
I appreciate the information about using GM only lubricants, but if this is what it costs, I would really like to know the following: Why are synthetics not good, What is the real problems they cause?
The posi additive is $12.54 for 4 ounces.
I cannot believe what GM charges for gear oil. Also, 23 ounces is not a full quart. I may need to purchase 3 containers of the 23 ounce stuff + posi additive.
$63.00 for gear lube, is it me or is this just a total rip off.?
I appreciate the information about using GM only lubricants, but if this is what it costs, I would really like to know the following: Why are synthetics not good, What is the real problems they cause?
AMSOIL Synthetic Gear Lube SAE 80w90 (Product Code AGLQT)
This gear lube comes with friction modifier already in it and most cars don't need more to prevent diff chatter. But if chatter occurs, this squeeze tube is easy to add a few oz of modifier and quiet the diff down:
AMSOIL Slip-Lock Differential Additive (Product Code ADATB)
For the DIYer:
AMSOIL Hand Pump (Product Code G2039)
Other than the Eaton link above, the others really don't come out strongly against or for synthetics, they just indicate that chatter may occur, which I would agree with. But, if it does, the fix is also as easy as adding a little modifier and you then have a better fluid and no chatter.
In answer to your question about what makes synthetics better, this AMSOIL study is a good read on what differentiates one gear lube from another:
AMSOIL Gear Lube “White Paper” (2 MB pdf file)
P.S. If you decide to go with the AMSOIL over the GM (or any other fluid), drop me a PM so I can ensure you get wholesale pricing, abuot 25% below retail, via the AMSOIL Preferred Customer Program.
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AMSOIL Preferred Customer Program (Members buy at Wholesale - a savings of about 25%)
C66 Racing #66 NASA ST2, SCCA T2
AMSOIL Dealer (Forum Vendor)
AMSOIL Preferred Customer Program (Members buy at Wholesale - a savings of about 25%)
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
Safety Car
Joined: Aug 2001
Posts: 4,883
Likes: 11
From: North Easton Mass
I used Lucas gear oil and 1 bottle of GM posi additive and so far no problems or noise. The diff has ~75,000 miles on it and nothing except side seals and a yoke have been replaced that I know of.
Rick B.
Rick B.