Does Amsoil have a 75w90 gear lube that meets all the same GM specs that the new GM 75w90 synthetic grape scented lubricant does?
A question for the Amsoil guys
- Thread starter PT1
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I'm going to say yes. The Severe Gear SVG 75W-90 and SVT 75W-110....BUT do you have a specification number? Is this a NEW, NEW purple juice?
The GM spec number is 9986115 which calls for GM lubricant part number 12378261. Which Mobil1 and Shell GL5 products do not meet according to them. I don't know what is in this spec that makes it so special because the applications are all mostly AAM axles with locker diffs. They also say NOT to add friction modifier. Beats me? Except GM wants $26/qt.
dnewton3
Staff member
I went round and round on this topic on another site. Here's what I gathered from all my research.
GM 9986115 is a spec that calls for "syntehtic" 75w-90 hypoid gear oil, with friction modifier added, for convenient sale across the GM parts counter. Seems that they have a spec for the factory fill oil, and a spec for the factory fill FM, so they had to create an additional spec to blend the two together for sale in the bottle to the public. There is no real mystery to 9986115 execpt that GM wants an arm, leg, and another body part for that little quart bottle.
Regarding the differential itself, here is a link that explains the need for lubricants. http://www.swedishbricks.net/700900FAQ/Driveline1.html
In the link, read down about 1/2 way to where you get to a quote about "Automatic Locking Differential Lubricants" from a guy at Eaton Corp. They are the makers of the GM G-80 locker, which is in turn used by AAM, who makes most of GM's axles. The gentleman specifically addresses the fact that ANY GL-5 lube is fine, and that they perform better with FM added. He mentions Texaco products by name, but he CLEARLY states that ANY GL-5 will suffice. He even mentions "mineral" lube as well as "synthetic" lube. The FM has nothing to do with the reliability of the G-80 locker; it is to address the small actuation clutch used in initiating the locker function. So, a FM helps quite the chatter, which in turn helps quiet customer complaints.
As for aftermarket lubes, ANY GL-5 will work. Notable "synthetic" fluids that are fine are Mobil 1, Syntec, Synpower, Severe Gear, and others. As far as I know, the FM is already added to some, if not all, of these product's I've listed.
Just like engine and transmission oils, "synthetics" make the lube last longer in service. GM's spec of 9986115 is not REQUIRED if you read you manual closely; it's RECOMMENDED, not REQUIRED. A GL-5 is required, but they only publish a spec number (9986115) to make you feel compelled to buy the "grape juice", because it seems like some type of "new, special, ultra-important" fluid.
There is a site where you can actually PURCHASE the specs for 9986115. It costs $20 or so, and it's not worth it, if you ask me.
You'll also see where it' describs the addition of FM to the fluid. http://auto.ihs.com/document/abstract/KCMJEBAAAAAAAAAA
Here's another link:
http://engineering-standards.globalspec....&show=standards
Another thing I learned is that the spec 9986115 really dates back to the 1990's, AFA I can tell. In fact, it's titled "fuel efficient hypoid gear oil" in it's GM header. It's nothing more than GM's effort to raise CAFE ratings.
Bottom line. The differential will live a long and happy life on any GL-5 fluid. Add in FM if it's not already included in the product your bought, so the small clutch won't occasionally shudder. Use a "synthetic" if you don't want to change the fluid as often. GM 9986115 is just another way of them getting more of your (presumably) hard earned dollars than they deserve, when you buy their "grape juice".
It sure does smell better though ...
GM 9986115 is a spec that calls for "syntehtic" 75w-90 hypoid gear oil, with friction modifier added, for convenient sale across the GM parts counter. Seems that they have a spec for the factory fill oil, and a spec for the factory fill FM, so they had to create an additional spec to blend the two together for sale in the bottle to the public. There is no real mystery to 9986115 execpt that GM wants an arm, leg, and another body part for that little quart bottle.
Regarding the differential itself, here is a link that explains the need for lubricants. http://www.swedishbricks.net/700900FAQ/Driveline1.html
In the link, read down about 1/2 way to where you get to a quote about "Automatic Locking Differential Lubricants" from a guy at Eaton Corp. They are the makers of the GM G-80 locker, which is in turn used by AAM, who makes most of GM's axles. The gentleman specifically addresses the fact that ANY GL-5 lube is fine, and that they perform better with FM added. He mentions Texaco products by name, but he CLEARLY states that ANY GL-5 will suffice. He even mentions "mineral" lube as well as "synthetic" lube. The FM has nothing to do with the reliability of the G-80 locker; it is to address the small actuation clutch used in initiating the locker function. So, a FM helps quite the chatter, which in turn helps quiet customer complaints.
As for aftermarket lubes, ANY GL-5 will work. Notable "synthetic" fluids that are fine are Mobil 1, Syntec, Synpower, Severe Gear, and others. As far as I know, the FM is already added to some, if not all, of these product's I've listed.
Just like engine and transmission oils, "synthetics" make the lube last longer in service. GM's spec of 9986115 is not REQUIRED if you read you manual closely; it's RECOMMENDED, not REQUIRED. A GL-5 is required, but they only publish a spec number (9986115) to make you feel compelled to buy the "grape juice", because it seems like some type of "new, special, ultra-important" fluid.
There is a site where you can actually PURCHASE the specs for 9986115. It costs $20 or so, and it's not worth it, if you ask me.
You'll also see where it' describs the addition of FM to the fluid. http://auto.ihs.com/document/abstract/KCMJEBAAAAAAAAAA
Here's another link:
http://engineering-standards.globalspec....&show=standards
Another thing I learned is that the spec 9986115 really dates back to the 1990's, AFA I can tell. In fact, it's titled "fuel efficient hypoid gear oil" in it's GM header. It's nothing more than GM's effort to raise CAFE ratings.
Bottom line. The differential will live a long and happy life on any GL-5 fluid. Add in FM if it's not already included in the product your bought, so the small clutch won't occasionally shudder. Use a "synthetic" if you don't want to change the fluid as often. GM 9986115 is just another way of them getting more of your (presumably) hard earned dollars than they deserve, when you buy their "grape juice".
It sure does smell better though ...
Last edited:
dnewton3
Staff member
Also, I forgot to include Amsoil's answer. I DO NOT USE, NOR SELL, AMSOIL! And I appologive if I'm stepping on Amsoil toes. But you asked a specific question, and you deserve a specific answer. In my mind, Amsoil is neither the savior, nor the demon; it's a brand choice like any other competitor in a free market enterprise system. And I support consumer choice, which is capitalism at it's finest!
Google "amsoil gm 9986115" and it should give you a direct link to the Amsoil answer about the lube you seek. It's labeled as a TSB from Amsoil in the actual text.
Google "amsoil gm 9986115" and it should give you a direct link to the Amsoil answer about the lube you seek. It's labeled as a TSB from Amsoil in the actual text.
Last edited:
Here's the TSB in question:
http://www.amsoil.com/dealer/techservicesbulletin/GM_steerable_rear_axles.pdf
And yes SVG or SVT (depending of the viscosity needed)
http://www.amsoil.com/dealer/techservicesbulletin/GM_steerable_rear_axles.pdf
And yes SVG or SVT (depending of the viscosity needed)
Originally Posted By: Pablo
Here's the TSB in question:
http://www.amsoil.com/dealer/techservicesbulletin/GM_steerable_rear_axles.pdf
And yes SVG or SVT (depending of the viscosity needed)
Do I need the friction modifier with the SVG or SVT? Or is it already in there?
Here's the TSB in question:
http://www.amsoil.com/dealer/techservicesbulletin/GM_steerable_rear_axles.pdf
And yes SVG or SVT (depending of the viscosity needed)
Do I need the friction modifier with the SVG or SVT? Or is it already in there?
It has some, try it without. Add as needed.
fyi
Quote:
Info - Rear Axle Lubricant Compatibility and Usage #99-04-20-001 - (06/18/1999)
Rear Axle Lubricant Compatibility and Usage
1988-99 Chevrolet and GMC C/K, G Van and P1-3 Series Models
1999 Cadillac Escalade
Built after the VIN Breakpoints (C/K) listed below:
This bulletin is being revised to add the 1999 Model Year, VIN Breakpoint information, and additional text. Please discard Corporate Bulletin Number 86-42-04 (Section 4 - Driveline/Axle).
VIN break points omitted...........
This bulletin is being issued to inform dealers about the compatibility and usage of the new Fuel Efficient SAE 75W-90 Synthetic Axle Lubricant, GM P/N 12378261 (In Canada use P/N 10953455), with current axles, and with the non-synthetic axle lubricant, GM P/N 1052271 (In Canada use P/N 10950849), for the rear axles on the above light-duty trucks.
Testing has shown that the new synthetic lubricant will chemically attack the Room Temperature Vulcanizing (RTV) sealant. Use only the non-synthetic lubricant, P/N 1052271, in axles using RTV sealant (See 9.5 and 10.5 information below).
American Axle and Manufacturing (A.A.M.) has approved the use of the new Fuel Efficient SAE 75W-90 synthetic axle lubricant for rear axles with the following restrictions:
All 8.6 inch axles are compatible as originally built.
9.5 inch axles on vehicles built prior to mid-February 1998 are NOT compatible because RTV sealant is used on the cover pans. On vehicles built after mid-February 1998 and equipped with 9.5 inch rear axles, synthetic lubricant, P/N 12378261, can be used because the RTV was replaced with a gasket. Other mid-February changes to the 9.5 inch rear axles include a new cover pan and cover pan fasteners common to other axles.
Important
The new cover pan is not retro-fittable to the housing of 9.5 inch axles on vehicles built prior to mid-February 1998. A new retrofit kit is available that will enable the use of synthetic lubricant for vehicles built after mid-February, 1998.
All 10.5 inch axles prior to March 3, 1999 are compatible if the axle shaft hub seal (RTV) is replaced with P/N 327739 gasket when changing to synthetic lubricant.
As a product improvement, this new lubricant has been released into 1999 current production C/K vehicles built after the above VIN breakpoints (Except HD3500 models which use 75W-140 synthetic lubricant, P/N 12346140).
It is recommended that synthetic lubricant be used when changing rear axle lubricant for the following reasons:
Potential fuel economy
Lower operating temperature under severe usage conditions
Important
You do not need to wash/rinse any non-synthetic lubricant from the axle cavity when changing over to a synthetic lubricant. However, you should remove debris from the magnet and the bottom of the axle cavity whenever the axle fluid is changed.
On light-duty trucks equipped with locking differentials, do NOT use a limited-slip additive.
Parts Information
P/N
Description
Quantity
327739
Gasket, Axle Shaft Seal
1
12378261
(In Canada use P/N 10953455)
Fuel Efficient SAE 75W-90 Synthetic Axle Lubricant
1
1052271
(In Canada use P/N 10950849)
Non-Synthetic Lubricant
1
12471310
Kit, 9.5 Inch Axle Cover Pan
1
Parts are currently available from GMSPO.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
© Copyright General Motors Corporation. All Rights Reserved.
Quote:
LOCKING DIFFERENTIAL LUBRICANT (SERVICE INFORMATION) #91-4-109
SUBJECT: LOCKING DIFFERENTIAL (G80) LUBRICANT - (SERVICE INFORMATION)
VEHICLES AFFECTED: ALL LIGHT TRUCKS EQUIPPED WITH G80 REAR AXLE ALL YEARS
Some light duty trucks equipped with locking rear axles (G80) may exhibit rear axle chatter, especially when turning a corner from a stop.
This condition of alternate engagement and disengagement of clutches in differential assembly is usually caused by contaminated axle lubricant.
To correct this condition, drain and refill the rear axle with SAE 75W-90 GL5 (P/N). The use of any additive in locking rear axles (G80) is not recommended. Rear axle additives are designed for use in limited slip differentials which are normally installed in cars. All light duty trucks equipped with RPO G80 make use of a locking differential and the use of additives will delay the engagement of the locking mechanism and may decrease axle life.
VEHICLES/COMPONENTS INVOLVED: ----------------------------- Some light duty trucks equipped with locking rear axles, RPO G80.
SERVICE PARTS INFORMATION:
Part Number Description ----------- ------------------ Lubricant, Rear Axle (1 litre)
Parts are currently available through CANSPO.
WARRANTY INFORMATION:
As specified in Light Duty Truck Maintenance Schedules, locking rear axle fluid drain and refill is required owner maintenance at the first engine oil change. Failure to drain and refill the rear axle as specified may contribute to a later axle chatter condition. Refer to the appropriate Light Duty Truck Maintenance Schedule or service manual, section OB, for further details on change intervals.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
© Copyright General Motors Corporation. All Rights Reserved.
Quote:
Info - Rear Axle Lubricant Compatibility and Usage #99-04-20-001 - (06/18/1999)
Rear Axle Lubricant Compatibility and Usage
1988-99 Chevrolet and GMC C/K, G Van and P1-3 Series Models
1999 Cadillac Escalade
Built after the VIN Breakpoints (C/K) listed below:
This bulletin is being revised to add the 1999 Model Year, VIN Breakpoint information, and additional text. Please discard Corporate Bulletin Number 86-42-04 (Section 4 - Driveline/Axle).
VIN break points omitted...........
This bulletin is being issued to inform dealers about the compatibility and usage of the new Fuel Efficient SAE 75W-90 Synthetic Axle Lubricant, GM P/N 12378261 (In Canada use P/N 10953455), with current axles, and with the non-synthetic axle lubricant, GM P/N 1052271 (In Canada use P/N 10950849), for the rear axles on the above light-duty trucks.
Testing has shown that the new synthetic lubricant will chemically attack the Room Temperature Vulcanizing (RTV) sealant. Use only the non-synthetic lubricant, P/N 1052271, in axles using RTV sealant (See 9.5 and 10.5 information below).
American Axle and Manufacturing (A.A.M.) has approved the use of the new Fuel Efficient SAE 75W-90 synthetic axle lubricant for rear axles with the following restrictions:
All 8.6 inch axles are compatible as originally built.
9.5 inch axles on vehicles built prior to mid-February 1998 are NOT compatible because RTV sealant is used on the cover pans. On vehicles built after mid-February 1998 and equipped with 9.5 inch rear axles, synthetic lubricant, P/N 12378261, can be used because the RTV was replaced with a gasket. Other mid-February changes to the 9.5 inch rear axles include a new cover pan and cover pan fasteners common to other axles.
Important
The new cover pan is not retro-fittable to the housing of 9.5 inch axles on vehicles built prior to mid-February 1998. A new retrofit kit is available that will enable the use of synthetic lubricant for vehicles built after mid-February, 1998.
All 10.5 inch axles prior to March 3, 1999 are compatible if the axle shaft hub seal (RTV) is replaced with P/N 327739 gasket when changing to synthetic lubricant.
As a product improvement, this new lubricant has been released into 1999 current production C/K vehicles built after the above VIN breakpoints (Except HD3500 models which use 75W-140 synthetic lubricant, P/N 12346140).
It is recommended that synthetic lubricant be used when changing rear axle lubricant for the following reasons:
Potential fuel economy
Lower operating temperature under severe usage conditions
Important
You do not need to wash/rinse any non-synthetic lubricant from the axle cavity when changing over to a synthetic lubricant. However, you should remove debris from the magnet and the bottom of the axle cavity whenever the axle fluid is changed.
On light-duty trucks equipped with locking differentials, do NOT use a limited-slip additive.
Parts Information
P/N
Description
Quantity
327739
Gasket, Axle Shaft Seal
1
12378261
(In Canada use P/N 10953455)
Fuel Efficient SAE 75W-90 Synthetic Axle Lubricant
1
1052271
(In Canada use P/N 10950849)
Non-Synthetic Lubricant
1
12471310
Kit, 9.5 Inch Axle Cover Pan
1
Parts are currently available from GMSPO.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
© Copyright General Motors Corporation. All Rights Reserved.
Quote:
LOCKING DIFFERENTIAL LUBRICANT (SERVICE INFORMATION) #91-4-109
SUBJECT: LOCKING DIFFERENTIAL (G80) LUBRICANT - (SERVICE INFORMATION)
VEHICLES AFFECTED: ALL LIGHT TRUCKS EQUIPPED WITH G80 REAR AXLE ALL YEARS
Some light duty trucks equipped with locking rear axles (G80) may exhibit rear axle chatter, especially when turning a corner from a stop.
This condition of alternate engagement and disengagement of clutches in differential assembly is usually caused by contaminated axle lubricant.
To correct this condition, drain and refill the rear axle with SAE 75W-90 GL5 (P/N). The use of any additive in locking rear axles (G80) is not recommended. Rear axle additives are designed for use in limited slip differentials which are normally installed in cars. All light duty trucks equipped with RPO G80 make use of a locking differential and the use of additives will delay the engagement of the locking mechanism and may decrease axle life.
VEHICLES/COMPONENTS INVOLVED: ----------------------------- Some light duty trucks equipped with locking rear axles, RPO G80.
SERVICE PARTS INFORMATION:
Part Number Description ----------- ------------------ Lubricant, Rear Axle (1 litre)
Parts are currently available through CANSPO.
WARRANTY INFORMATION:
As specified in Light Duty Truck Maintenance Schedules, locking rear axle fluid drain and refill is required owner maintenance at the first engine oil change. Failure to drain and refill the rear axle as specified may contribute to a later axle chatter condition. Refer to the appropriate Light Duty Truck Maintenance Schedule or service manual, section OB, for further details on change intervals.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.
© Copyright General Motors Corporation. All Rights Reserved.
Thanks for all the replies. I have a 2006 8.6 rear axle AWD and the service manual specifically spec.s this GM fluid.
in both front & rear diffs and dexIII
in the transfer case. I did do the break-in fluid change out once ( the dealer I was getting my service done at charged me much less for the gear oil) and removed all the debris. I also switched the tcase to Mobil1 synthetic atf which runs real quiet now. So I will probably start looking for a less expensive alternative since the dealer that charged me less has since closed. I wish I had known because I would have bought a case of the stuff. I may just try the amsoil and split a can of FM between the two diffs.
dnewton3
Staff member
If I'm not mistaken, the Amsoil products already have the FM added.
Regarding the t-case (a bit off topic, but you brought it up) you will want to be concerned about the possibility of a condition called "pump rub". Go over to thedieselplace and check it out in the drive train section. Further, there is lot's of banter about the use of 5w30 synthetic motor oil in the t-case instead of ATF, but I'm not a proponent of that. I used Mobil 1 ATF and it's working fantastic.
Regarding the t-case (a bit off topic, but you brought it up) you will want to be concerned about the possibility of a condition called "pump rub". Go over to thedieselplace and check it out in the drive train section. Further, there is lot's of banter about the use of 5w30 synthetic motor oil in the t-case instead of ATF, but I'm not a proponent of that. I used Mobil 1 ATF and it's working fantastic.
Originally Posted By: dnewton3
If I'm not mistaken, the Amsoil products already have the FM added.
Regarding the t-case (a bit off topic, but you brought it up) you will want to be concerned about the possibility of a condition called "pump rub". Go over to thedieselplace and check it out in the drive train section. Further, there is lot's of banter about the use of 5w30 synthetic motor oil in the t-case instead of ATF, but I'm not a proponent of that. I used Mobil 1 ATF and it's working fantastic.
There is no pump in my Borg Warner tcase. Strictly a splash system that is vented so no internal pressure build up. That is why ATF is speced because it has to splash readily when cold. So everything in there is basically just swimming in ATF. There are no clutches or pumps just a huge chain and gearsets. The owners manual calls for a change every 50k so I'll change it out at 40k intervals.
If I'm not mistaken, the Amsoil products already have the FM added.
Regarding the t-case (a bit off topic, but you brought it up) you will want to be concerned about the possibility of a condition called "pump rub". Go over to thedieselplace and check it out in the drive train section. Further, there is lot's of banter about the use of 5w30 synthetic motor oil in the t-case instead of ATF, but I'm not a proponent of that. I used Mobil 1 ATF and it's working fantastic.
There is no pump in my Borg Warner tcase. Strictly a splash system that is vented so no internal pressure build up. That is why ATF is speced because it has to splash readily when cold. So everything in there is basically just swimming in ATF. There are no clutches or pumps just a huge chain and gearsets. The owners manual calls for a change every 50k so I'll change it out at 40k intervals.
Last edited:
dnewton3
Staff member
You are right; I stand corrected on the pump-rub issue. It only effects the 236, 246, 261, and 263 cases.
Last edited:
Well I scored 3 quarts of the famous GM grape scented 75w90 synthetic on ebay for $27 + $10 for shipping.
Much better than the $85 the dealer wants. I was surprised to see several people selling it on there.
Originally Posted By: PT1
Well I scored 3 quarts of the famous GM grape scented 75w90 synthetic on ebay for $27 + $10 for shipping.
Much better than the $85 the dealer wants. I was surprised to see several people selling it on there.
There is probably a dealer or two with some missing quarts!!
Well I scored 3 quarts of the famous GM grape scented 75w90 synthetic on ebay for $27 + $10 for shipping.
There is probably a dealer or two with some missing quarts!!
Originally Posted By: Donald
Originally Posted By: PT1
Well I scored 3 quarts of the famous GM grape scented 75w90 synthetic on ebay for $27 + $10 for shipping.
Much better than the $85 the dealer wants. I was surprised to see several people selling it on there.
There is probably a dealer or two with some missing quarts!!
That did cross my mind as there were several people all selling 3 quarts.
Originally Posted By: PT1
Well I scored 3 quarts of the famous GM grape scented 75w90 synthetic on ebay for $27 + $10 for shipping.
There is probably a dealer or two with some missing quarts!!
That did cross my mind as there were several people all selling 3 quarts.
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