NBS ??
Synthetic gear lube question
- Thread starter wtd
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My apologies, but the factory shop manual (published by Helm, Inc.) for my 2004 Avalanche states otherwise, and clearly indicates that the locking differential used contains both limited slip and mechanical locking qualities.
Additionally, if one looks at at both the factory schematic(s) and Eaton's website (with pretty neat movies I might add), it is confirmed that the G80 locker in my light duty truck is indeed a true locking differential.
Bob W.
Furor: n. A general commotion; public disorder or uproar. [Middle English furour, wrath, fury, from Old French fureur, from Latin furor, from furere, to rage.]
This is what I am trying to figure out: GM says synthetic grape juice, with additive built in, and Eaton says use 80w-90 conventional GL-5 with additive to be, er, added.
My suspicion is that GM specifies the use of synthetic for reasons other than differential longevity (maybe CAFE purposes, I don't know....).
Bob W.
Furor: n. A general commotion; public disorder or uproar. [Middle English furour, wrath, fury, from Old French fureur, from Latin furor, from furere, to rage.]
Well I replaced the rear dif fluid @1500 miles with the grape juice ($22/qt)
I want to change it again now that it has 40,000 miles on that oil and to try another brand.
So a asked Redline what to put in:
-----------------------------------------------
>Below are the results from the Red Line Oil web site Application
>It was placed on 2/6/2005 6:25:23 AM.
> Application Request Form Information
>-----------------------------------------------
>Make : Chevy
>Model : Silverado 2500HD
>Year : 2003
>Engine Type : 6.6 duramax
>Differential Size/Type : 3.75 G80 - Eaton Locking differential
>Transmission Type: Allison LCT 1000 Issues : Manual recommends:SAE
>75W-90 Synthetic Axle Lubricant(GM Part No. U.S. 12378261 or equivalent
>meeting GM Specification 9986115.
>Recommendations : Looking for a rear axle fluid recommendation:
>75W-90 NS, 75W-90 or a mix the two types. Or whatever you recommend.
John,
The Red Line 75W90 would be a suitable replacement for the fluid
called for in your differential and would satisfy the fluid
requirements.
Regards, Dave
Red Line Oil
I want to change it again now that it has 40,000 miles on that oil and to try another brand.
So a asked Redline what to put in:
-----------------------------------------------
>Below are the results from the Red Line Oil web site Application
>It was placed on 2/6/2005 6:25:23 AM.
> Application Request Form Information
>-----------------------------------------------
>Make : Chevy
>Model : Silverado 2500HD
>Year : 2003
>Engine Type : 6.6 duramax
>Differential Size/Type : 3.75 G80 - Eaton Locking differential
>Transmission Type: Allison LCT 1000 Issues : Manual recommends:SAE
>75W-90 Synthetic Axle Lubricant(GM Part No. U.S. 12378261 or equivalent
>meeting GM Specification 9986115.
>Recommendations : Looking for a rear axle fluid recommendation:
>75W-90 NS, 75W-90 or a mix the two types. Or whatever you recommend.
John,
The Red Line 75W90 would be a suitable replacement for the fluid
called for in your differential and would satisfy the fluid
requirements.
Regards, Dave
Red Line Oil
MolaKule
Staff member
The question to Dave at Redline should be similar to a question posed to SF:
Does this fluid MEET the 350,000 mile (or more) warranty requirements as per Eaton Warranty Requirements?
Redline OR Specialty Formulations 75W90 GL5 lubes would FUNCTION just fine in this differential, I have no doubt.
The main question that has to be applied fairly to both companies is:
Does this fluid or has this fluid been QUALIFIED by Eaton with respect to Eaton's warranty requirements?
I think the answer is no!
Does this fluid MEET the 350,000 mile (or more) warranty requirements as per Eaton Warranty Requirements?
Redline OR Specialty Formulations 75W90 GL5 lubes would FUNCTION just fine in this differential, I have no doubt.
The main question that has to be applied fairly to both companies is:
Does this fluid or has this fluid been QUALIFIED by Eaton with respect to Eaton's warranty requirements?
I think the answer is no!
New body style.
I think it may be CAFE related as well. The dealer told me that for 2005 the front differential on the 4x4s has the same "grape juice" synthetic that the rear has had for a few years.quote:
Originally posted by TheFuror:
This is what I am trying to figure out: GM says synthetic grape juice, with additive built in, and Eaton says use 80w-90 conventional GL-5 with additive to be, er, added.
My suspicion is that GM specifies the use of synthetic for reasons other than differential longevity (maybe CAFE purposes, I don't know....).
Bob W.
Furor: n. A general commotion; public disorder or uproar. [Middle English furour, wrath, fury, from Old French fureur, from Latin furor, from furere, to rage.]
I think it may be CAFE related as well. The dealer told me that for 2005 the front differential on the 4x4s has the same "grape juice" synthetic that the rear has had for a few years.
Interesting...
I know that previous to 2005 the "full time" four wheel drives used the grape juice, as opposed to the 80w-90 for the select four wheel drive.
Here is something else: for my truck the factory manual says use a certain GM part # or 80w-90 GL-5. however, when I looked at the GM gear oil bottle, it says "exceeds GL-4" and no mention of GL-5 specs.
What gives with this?
Bob W.
Furor: n. A general commotion; public disorder or uproar. [Middle English furour, wrath, fury, from Old French fureur, from Latin furor, from furere, to rage.]
MolaKule
Staff member
Please clarify. Does this statement apply to the Eatons in the Chevy trucks with the Grape Juice-colored fluid?
It's starting to make some sense now..... The GM axle with the G80 needs a friction modifier as it's evidently using a clutch pac, while the current Dodge axles use a gear based Torsen limited slip which doesn't need a friction modifier. In fact, it appears that using a friction modifier in the Torsen might result in more noise/chatter. Like I mentioned earlier, some limited slips are picky about fluids.
I looked in my owner's manual and my Helm factory service manual for my 98 Silverado and neither one says to add any friction modifier to the rear end fluid if you have the locking differential. It just says to use a GL-5 80W-90 weight oil.
As for my noise problem, I changed out the U-joints today and replaced the rear end fluid with 80W-90 Castrol Hypoy C conventional diff fluid with no change in the noise. I tried the Castrol fluid because I wanted to see if the slightly thicker oil would change the noise.
I believe jsharp is right and that it is my pinion bearing going out. So much for synthetic gear lube extending the life of my differential.
To say the least, I'm not very happy right now. Most people never change the diff fluid and never have problems. I've changed the diff fluid four times in mine, using Mobil 1 synthetic for most of its life, and its going out at only 76,700 miles. I must have bad luck or something.
Wayne
As for my noise problem, I changed out the U-joints today and replaced the rear end fluid with 80W-90 Castrol Hypoy C conventional diff fluid with no change in the noise. I tried the Castrol fluid because I wanted to see if the slightly thicker oil would change the noise.
I believe jsharp is right and that it is my pinion bearing going out. So much for synthetic gear lube extending the life of my differential.
To say the least, I'm not very happy right now. Most people never change the diff fluid and never have problems. I've changed the diff fluid four times in mine, using Mobil 1 synthetic for most of its life, and its going out at only 76,700 miles. I must have bad luck or something.
Wayne
Its not the U-joints because I just replaced both of the rear ones yesterday.
Wayne
Wayne
The rearend in my truck doesn't chatter, its more of a whine. I had the fluid first changed at the time of my first oil change but started using Mobil 1 at about 20,000 miles. When I changed it again last april, I had about 44,000 miles on the lube. Maybe that was too long to leave it in. I think I'm just going to stick with conventional rearend lube and change it every 15,000 miles.
Wayne
Wayne
MolaKule
Staff member
This is what I been trying to convince people to do for some time.
You might want to try our heavy duty HDS-5 from Specialty Formulations.
This normal, my work truck (99 K2500 subruban) used to whine all the time and it had the OEM fluid in it till the day the lease was up at around 125,000 mile.
The whine is from the ring and pinion and not the locking differential. Gears meshing are going to make noise.
Info - Recommended Rear Axle Lubricant #01-00-90-001A
Recommended Rear Axle Lubricant
2000-01 Rear Wheel Drive Passenger Cars, Light Duty Trucks and Four Wheel Drive Vehicles
This bulletin is being revised to update the model year information in the table below. Please discard Corporate Bulletin 01-00-90-001 (Section 00 -- General Information).
The following table provides the latest information on recommended rear axle lubricant.
Model Year(s)
Model(s)
Usage
Recommended Lubricant
Recommended Maintenance
2000-1
Cadillac Catera
Rear Axle
SAE 80W-90 GL-5 Axle Lubricant, GM P/N 12345977 (in Canada use P/N 10953482) or equivalent.
Check axle fluid level and add fluid as needed every 30,000 miles (48 000 km).
2000
Cadillac Escalade
Rear Axle
SAE 75W-90 Synthetic Axle Lubricant, GM P/N 12378261 (in Canada use P/N 10953455) or equivalent meeting GM Specification 9986115.
Short Trip/City Intervals: Check axle fluid level and add fluid as needed every 3,000 miles (5 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2000
Chevrolet Astro/Express, GMC Safari/Savana
Rear Axle (Standard)
SAE 80W-90 Axle Lubricant, GM P/N 1052271 (in Canada use P/N 10950849 or equivalent.
If driving in dusty areas or when towing a trailer, drain fluid and refill every 15,000 miles (25 000 km).
Short Trip/City Intervals: Check axle fluid level and add fluid as needed every 3,000 miles (5 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2000
Chevrolet Astro/Express, GMC Safari/Savana
Rear Axle (Locking Differential)
Axle Lubricant, use only GM P/N 1052271 (in Canada use P/N 10950849). Do not add friction modifier.
If driving in dusty areas or when towing a trailer, drain fluid and refill every 15,000 miles (25 000 km).
Drain fluid and refill at first engine oil change.
Short Trip/City Intervals: Check axle fluid level and add fluid as needed every 3,000 miles (5 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2000-1
Chevrolet Blazer/S10, GMC Envoy/Jimmy/Sonoma
Rear Axle (Standard)
SAE 80W-90 Axle Lubricant, GM P/N 1052271 (in Canada use P/N 10950849) or equivalent.
If driving in dusty areas or when towing a trailer, drain fluid and refill every 15,000 miles (25 000 km).
Short Trip/City Intervals: Check axle fluid level and add fluid as needed every 3,000 miles (5 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2000-1
Chevrolet Blazer/S10, GMC Envoy/Jimmy/Sonoma
Rear Axle (Locking Differential)
Axle Lubricant, use only GM P/N 1052271 (in Canada use P/N 10950849). Do not add friction modifier.
If driving in dusty areas or when towing a trailer, drain fluid and refill every 15,000 miles (25 000 km).
Drain fluid and refill at first engine oil change.
Short Trip/City Intervals: Check axle fluid level and add fluid as needed every 3,000 miles (5 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2000-1
Chevrolet Camaro, Pontiac Firebird
Rear Axle (Standard)
SAE 75W-90 Synthetic Axle Lubricant, GM P/N 12378261 (in Canada use P/N 10953455) or equivalent meeting GM Specification 9986115.
Check axle fluid level and add fluid as needed at least twice a year (for instance, each spring and fall).
2000-1
Chevrolet Camaro/ Corvette, Pontiac Firebird
Rear Axle (Limited Slip)
SAE 75W-90 Synthetic Axle Lubricant, GM P/N 12378261 (in Canada use P/N 10953455) or equivalent meeting GM Specification 9986115. With complete drain and refill, add 4 ounces (118 ml) of Limited Slip Axle Lubricant Additive, GM P/N 1052358 (in Canada use P/N 992694) or equivalent.
Check axle fluid level and add fluid as needed at least twice a year (for instance, each spring and fall).
2000-1
Chevrolet Silverado/Suburban/Tahoe, GMC Denali/Sierra/Yukon/Yukon XL
Rear Axle
SAE 75W-90 Synthetic Axle Lubricant, GM P/N 12378261 (in Canada use P/N 10953455) or equivalent meeting GM Specification 9986115.
Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2000-1
Chevrolet Tracker
Rear Axle
SAE 80W-90 GL-5 Axle Lubricant, GM P/N 12345977 (in Canada use P/N 10953482) or equivalent.
Short Trip/City Intervals: Change differential fluid every 15,000 miles (25 000 km).
Long Trip/Highway Intervals: Change differential fluid every 30,000 miles (50 000 km).
2000-1
Oldsmobile Bravada
Rear Axle (Locking Differential)
Axle Lubricant, use only GM Part No.1052271 (in Canada use P/N 10950849). Do not add friction modifier.
If driving in dusty areas or when towing a trailer, drain fluid and refill every 15,000 miles (25 000 km).
Drain fluid and refill at first engine oil change.
Short Trip/City Intervals: Check axle fluid level and add fluid as needed every 3,000 miles (5 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2001
Chevrolet Astro, GMC Safari
Rear Axle (Standard, Locking Differential)
SAE 75W-90 Synthetic Axle Lubricant, GM P/N 12378261 (in Canada use P/N 10953455) or equivalent meeting GM Specification 9986115.
Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2001
Chevrolet Express, GMC Savana
8.6 Inch, Rear Axle Only (Standard, Locking Differential)
SAE 75W-90 Synthetic Axle Lubricant, GM P/N 12378261 (in Canada use P/N 10953455) or equivalent meeting GM Specification 9986115.
Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2001
Chevrolet Express, GMC Savana
9.5, 10.5 Inch Rear Axles (Standard)
SAE 80W-90 Axle Lubricant, GM P/N 1052271 (in Canada use P/N 10950849) or equivalent.
If driving in dusty areas or when towing a trailer, drain fluid and refill every 15,000 miles (25 000 km).
Short Trip/City Intervals: Check axle fluid level and add fluid as needed every 3,000 miles (5 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2001
Chevrolet Express, GMC Savana
9.5, 10.5 Inch Rear Axles (Locking Differential)
Axle Lubricant, use only GM P/N 1052271 (in Canada use P/N 10950849). Do not add friction modifier.
If driving in dusty areas or when towing a trailer, drain fluid and refill every 15,000 miles (25 000 km).
Drain fluid and refill at first engine oil change.
Short Trip/City Intervals: Check axle fluid level and add fluid as needed every 3,000 miles (5 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2001
Chevrolet 3500 HD, GMC Sierra 3500 HD
Rear Axle
SAE 75W-140 Synthetic Axle Lubricant, GM P/N 12346140 (in Canada use P/N 10953492) or equivalent.
Short Trip/City Intervals: Check axle fluid level and add as needed every 3,000 miles (5 000 km). Change axle fluid if the vehicle is driven in extreme overload, trailer towing and/or high-speed (above 40 mph or 70 km/h) conditions for extended periods of time every 30,000 miles (50 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add as needed every 7,500 miles (12 500 km). Change axle fluid with high-speed use every 30,000 miles (50 000 km).
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.
Recommended Rear Axle Lubricant
2000-01 Rear Wheel Drive Passenger Cars, Light Duty Trucks and Four Wheel Drive Vehicles
This bulletin is being revised to update the model year information in the table below. Please discard Corporate Bulletin 01-00-90-001 (Section 00 -- General Information).
The following table provides the latest information on recommended rear axle lubricant.
Model Year(s)
Model(s)
Usage
Recommended Lubricant
Recommended Maintenance
2000-1
Cadillac Catera
Rear Axle
SAE 80W-90 GL-5 Axle Lubricant, GM P/N 12345977 (in Canada use P/N 10953482) or equivalent.
Check axle fluid level and add fluid as needed every 30,000 miles (48 000 km).
2000
Cadillac Escalade
Rear Axle
SAE 75W-90 Synthetic Axle Lubricant, GM P/N 12378261 (in Canada use P/N 10953455) or equivalent meeting GM Specification 9986115.
Short Trip/City Intervals: Check axle fluid level and add fluid as needed every 3,000 miles (5 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2000
Chevrolet Astro/Express, GMC Safari/Savana
Rear Axle (Standard)
SAE 80W-90 Axle Lubricant, GM P/N 1052271 (in Canada use P/N 10950849 or equivalent.
If driving in dusty areas or when towing a trailer, drain fluid and refill every 15,000 miles (25 000 km).
Short Trip/City Intervals: Check axle fluid level and add fluid as needed every 3,000 miles (5 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2000
Chevrolet Astro/Express, GMC Safari/Savana
Rear Axle (Locking Differential)
Axle Lubricant, use only GM P/N 1052271 (in Canada use P/N 10950849). Do not add friction modifier.
If driving in dusty areas or when towing a trailer, drain fluid and refill every 15,000 miles (25 000 km).
Drain fluid and refill at first engine oil change.
Short Trip/City Intervals: Check axle fluid level and add fluid as needed every 3,000 miles (5 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2000-1
Chevrolet Blazer/S10, GMC Envoy/Jimmy/Sonoma
Rear Axle (Standard)
SAE 80W-90 Axle Lubricant, GM P/N 1052271 (in Canada use P/N 10950849) or equivalent.
If driving in dusty areas or when towing a trailer, drain fluid and refill every 15,000 miles (25 000 km).
Short Trip/City Intervals: Check axle fluid level and add fluid as needed every 3,000 miles (5 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2000-1
Chevrolet Blazer/S10, GMC Envoy/Jimmy/Sonoma
Rear Axle (Locking Differential)
Axle Lubricant, use only GM P/N 1052271 (in Canada use P/N 10950849). Do not add friction modifier.
If driving in dusty areas or when towing a trailer, drain fluid and refill every 15,000 miles (25 000 km).
Drain fluid and refill at first engine oil change.
Short Trip/City Intervals: Check axle fluid level and add fluid as needed every 3,000 miles (5 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2000-1
Chevrolet Camaro, Pontiac Firebird
Rear Axle (Standard)
SAE 75W-90 Synthetic Axle Lubricant, GM P/N 12378261 (in Canada use P/N 10953455) or equivalent meeting GM Specification 9986115.
Check axle fluid level and add fluid as needed at least twice a year (for instance, each spring and fall).
2000-1
Chevrolet Camaro/ Corvette, Pontiac Firebird
Rear Axle (Limited Slip)
SAE 75W-90 Synthetic Axle Lubricant, GM P/N 12378261 (in Canada use P/N 10953455) or equivalent meeting GM Specification 9986115. With complete drain and refill, add 4 ounces (118 ml) of Limited Slip Axle Lubricant Additive, GM P/N 1052358 (in Canada use P/N 992694) or equivalent.
Check axle fluid level and add fluid as needed at least twice a year (for instance, each spring and fall).
2000-1
Chevrolet Silverado/Suburban/Tahoe, GMC Denali/Sierra/Yukon/Yukon XL
Rear Axle
SAE 75W-90 Synthetic Axle Lubricant, GM P/N 12378261 (in Canada use P/N 10953455) or equivalent meeting GM Specification 9986115.
Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2000-1
Chevrolet Tracker
Rear Axle
SAE 80W-90 GL-5 Axle Lubricant, GM P/N 12345977 (in Canada use P/N 10953482) or equivalent.
Short Trip/City Intervals: Change differential fluid every 15,000 miles (25 000 km).
Long Trip/Highway Intervals: Change differential fluid every 30,000 miles (50 000 km).
2000-1
Oldsmobile Bravada
Rear Axle (Locking Differential)
Axle Lubricant, use only GM Part No.1052271 (in Canada use P/N 10950849). Do not add friction modifier.
If driving in dusty areas or when towing a trailer, drain fluid and refill every 15,000 miles (25 000 km).
Drain fluid and refill at first engine oil change.
Short Trip/City Intervals: Check axle fluid level and add fluid as needed every 3,000 miles (5 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2001
Chevrolet Astro, GMC Safari
Rear Axle (Standard, Locking Differential)
SAE 75W-90 Synthetic Axle Lubricant, GM P/N 12378261 (in Canada use P/N 10953455) or equivalent meeting GM Specification 9986115.
Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2001
Chevrolet Express, GMC Savana
8.6 Inch, Rear Axle Only (Standard, Locking Differential)
SAE 75W-90 Synthetic Axle Lubricant, GM P/N 12378261 (in Canada use P/N 10953455) or equivalent meeting GM Specification 9986115.
Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2001
Chevrolet Express, GMC Savana
9.5, 10.5 Inch Rear Axles (Standard)
SAE 80W-90 Axle Lubricant, GM P/N 1052271 (in Canada use P/N 10950849) or equivalent.
If driving in dusty areas or when towing a trailer, drain fluid and refill every 15,000 miles (25 000 km).
Short Trip/City Intervals: Check axle fluid level and add fluid as needed every 3,000 miles (5 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2001
Chevrolet Express, GMC Savana
9.5, 10.5 Inch Rear Axles (Locking Differential)
Axle Lubricant, use only GM P/N 1052271 (in Canada use P/N 10950849). Do not add friction modifier.
If driving in dusty areas or when towing a trailer, drain fluid and refill every 15,000 miles (25 000 km).
Drain fluid and refill at first engine oil change.
Short Trip/City Intervals: Check axle fluid level and add fluid as needed every 3,000 miles (5 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add fluid as needed every 7,500 miles (12 500 km).
2001
Chevrolet 3500 HD, GMC Sierra 3500 HD
Rear Axle
SAE 75W-140 Synthetic Axle Lubricant, GM P/N 12346140 (in Canada use P/N 10953492) or equivalent.
Short Trip/City Intervals: Check axle fluid level and add as needed every 3,000 miles (5 000 km). Change axle fluid if the vehicle is driven in extreme overload, trailer towing and/or high-speed (above 40 mph or 70 km/h) conditions for extended periods of time every 30,000 miles (50 000 km).
Long Trip/Highway Intervals: Check axle fluid level and add as needed every 7,500 miles (12 500 km). Change axle fluid with high-speed use every 30,000 miles (50 000 km).
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.
Mike,
If the whining was normal, why didn't it do it until the last year? Its also gotten louder in the recent few months. After thinking about it, I'm not for sure if its the pinion bearing or not. I don't have any movement or leakage at the pinion flange at the front of the diff. I would think that there would be some movement if the bearings were going bad but since I'm not an expert on rearends, I could be wrong. All I know is the noise is getting annoying.
With the rearend on jackstands and the truck running in neutral, the driveshaft looks like its slighly wobbleing toward the end where it bolts up to the rear diff. There isn't any abnormal vibrations when driving the truck so it must not be too out of round. Thanks for all of the input.
Wayne
If the whining was normal, why didn't it do it until the last year? Its also gotten louder in the recent few months. After thinking about it, I'm not for sure if its the pinion bearing or not. I don't have any movement or leakage at the pinion flange at the front of the diff. I would think that there would be some movement if the bearings were going bad but since I'm not an expert on rearends, I could be wrong. All I know is the noise is getting annoying.
With the rearend on jackstands and the truck running in neutral, the driveshaft looks like its slighly wobbleing toward the end where it bolts up to the rear diff. There isn't any abnormal vibrations when driving the truck so it must not be too out of round. Thanks for all of the input.
Wayne
Found this info TSB from GM, look at the bold print..
Pay no attention to the part numbers given in this TSB and or lube specs, they have been superceeded but I could get info.
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 80W-90 GL5 (P/N 10950849). 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 ----------- ------------------ 10950849 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.
[ February 12, 2005, 12:30 PM: Message edited by: Mike ]
Pay no attention to the part numbers given in this TSB and or lube specs, they have been superceeded but I could get info.
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 80W-90 GL5 (P/N 10950849). 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 ----------- ------------------ 10950849 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.
[ February 12, 2005, 12:30 PM: Message edited by: Mike ]
The whine is just harmonics caused by the meshing of gears. The presence of a whine in and of itself is not any indication of a problem. I have had many vehicles with rear gear whine and never let it bother me Btw-I would not add any FM addtive to a locking rear as mentioned in the GM TSB, it could cause problems. The best thing for it was the Mobil 1.
You can have a expert tear it apart and check it out, maybe when its put back together it will be setup more precisely and the noise will be gone But I think you may be chasing just a noise causd by improper setup of the ring and pinion and likely normal wear and tear. Its up to you, seek out a trans/axle expert and see what they say. They will be glad to take your money.
Go to Google and type "Gear Whine", you will find it a big concern..
Y. Cheng and T.C. Lim, “An Analysis of Rear Axle Gear Whine,” International Congress and Exposition on Noise Control Engineering, Dearborn, Michigan, 2002.
A.L. Dunn, D.R. Houser and T.C. Lim, “Methods for Researching Gear Whine in Automotive Transaxles,” Journal of Passenger Cars: Mechanical Systems, 108(6), pp. 2849–2858, 1999.
[ February 13, 2005, 10:55 AM: Message edited by: Mike ]
You can have a expert tear it apart and check it out, maybe when its put back together it will be setup more precisely and the noise will be gone But I think you may be chasing just a noise causd by improper setup of the ring and pinion and likely normal wear and tear. Its up to you, seek out a trans/axle expert and see what they say. They will be glad to take your money.
Go to Google and type "Gear Whine", you will find it a big concern..
Some reseach
Y. Cheng and T.C. Lim, “An Analysis of Rear Axle Gear Whine,” International Congress and Exposition on Noise Control Engineering, Dearborn, Michigan, 2002.
A.L. Dunn, D.R. Houser and T.C. Lim, “Methods for Researching Gear Whine in Automotive Transaxles,” Journal of Passenger Cars: Mechanical Systems, 108(6), pp. 2849–2858, 1999.
Vehicle sound quality and the reduction of gear whine is an issue of increasing
[ February 13, 2005, 10:55 AM: Message edited by: Mike ]
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