GM Axle Lubricant. Additive?
Thread Starter
Melting Slicks
Joined: Jan 2004
Posts: 3,138
Likes: 37
From: Burbank. CA.
GM Axle Lubricant. Additive?
For the last couple of years I have always used the 4oz. bottle of friction modifier to go with this oill. The guys at the counter said with this oil it's not necessary.
Do I believe them or not?
thanks,
Steve
Do I believe them or not?
thanks,
Steve
Team Owner
Joined: May 2001
Posts: 36,836
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Red Line also has it premixed too. I'm not certain on the GM lube. One thing's for sure, if it already contains FM, you don't want to add more. Only if you experience clutch chatter when cornering should you ever add more (a little at a time). Too much FM is a bad thing and will prevent your limited slip differential from operating as it was designed as it would allow too much slippage.Anyone here know if the GM is pre-mixed?
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Some of the GM fluids have been updated in the last couple of years and the part numbers identified in the service manual are superceded. I don't know the answer to your question, you need to ask someone knowledgable at GM. I would contact Gene Culley and get his input. Perhaps he can respond in this thread so we all have the information.
Burning Brakes
Joined: Jul 2004
Posts: 866
Likes: 5
From: Jensen Beach FL
My personal experience is that Amsoil needs the additive. Twice I have changed the rear fluid with Amsoil and both times the rear chattered and made noise while cornering until I added the GM Posi additive. After adding the additive I had no issues at all.
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Melting Slicks
Joined: Aug 2006
Posts: 3,279
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From: Fallbrook Califronia
Those of us that have had cars with limited slip rear ends have learned that the GM additive is best. I have used it in all brands of cars with limited slip diffs. Unless the oil you buy says it is for limited slip rear ends I would use the additive, and if it chatters add it anyway.
Intermediate
Joined: Sep 2006
Posts: 25
Likes: 0
From: Hartland Mi
OK since were on the subject whats the consciences out there on frequency of rear axle lube change? I recently took my 04 Silverado (39000 miles ) in for a oil change and the service writer asked if I wanted to have the axle fluid changed, I declinded but he got me thinking about it and this thread got me thinking about my 99 Vette. My truck has a limited slip axle and I guess its standard on all late model Vettes.
My truck owners manual dosen't even list the rear axle in it's maintenance schedule?
My truck owners manual dosen't even list the rear axle in it's maintenance schedule?
Race Director
Joined: Jan 2002
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From: I love you & miss you Linda
2017 C7 of the Year Finalist
St. Jude Contributor
Now unrelated to all this, am I reading that GM Axle Lube jug correctly above? Does it really say "New Grape Scent" ? or are my eyes worse that I thought they were..
Team Owner
Joined: May 2001
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From: Dear Karma, I have a list of people you missed.
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
I do NOT know the answer to your question, BUT I have learned that the GM 4oz additive is the best you can use. I use Royal Purple Max-Gear in my C5 which per RP does NOT need the additive. I added it anyway.....
Now unrelated to all this, am I reading that GM Axle Lube jug correctly above? Does it really say "New Grape Scent" ? or are my eyes worse that I thought they were..
Now unrelated to all this, am I reading that GM Axle Lube jug correctly above? Does it really say "New Grape Scent" ? or are my eyes worse that I thought they were..
Premium Supporting Vendor
Joined: Aug 2001
Posts: 5,364
Likes: 38
From: King George VA
The AMSOIL Severe Gear Extreme Pressure Synthetic 75w90 comes with the friction modifier pre-mixed in and adding a modifier such as the AMSOIL Slip-Lock Differential Additive is not normally needed. I've been using this fluid in my diff for years and have never experienced chatter. The vast majority of my customers do not use the additive. But there are exceptions such as MGorman above. AMSOIL recommends adding a bottle if your diff chatters.
In my opinion, adding extra additive will not break your diff. I believe that what happens is that the diff's limited slip ability will be reduced (e.g. more slip) and thus the unweighted tire will get more torque and more wheelspin. Thus the car will accelerate slower and have more inner wheel wheelspin.
In my opinion, adding extra additive will not break your diff. I believe that what happens is that the diff's limited slip ability will be reduced (e.g. more slip) and thus the unweighted tire will get more torque and more wheelspin. Thus the car will accelerate slower and have more inner wheel wheelspin.
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AMSOIL Preferred Customer Program (Members buy at Wholesale - a savings of about 25%)
