Re Oil A G80?

jdr7785 · July 12, 2011

I just bought a used 2005 silverado. I noticed that when i turned all the way left, the rear tire would skid and shake. After doing research i found out it was the G80. The dealer said all it needs is cleaned out and re oiled. After talking to other people, they claim that that is a big lie and that it needs to be replaced or taken back.

Any thoughts? I would really appreciate it

dlstewart01 · July 12, 2011

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 12378261). 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 ----------- ------------------ 12678261 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.

jdr7785 · July 12, 2011

Thanks,

This is just confusing because I have some people saying that the oil or lube is ok for them to do. Then i have people saying the g80 probably needs replaced.

brainpause · July 12, 2011

Thanks,

This is just confusing because I have some people saying that the oil or lube is ok for them to do. Then i have people saying the g80 probably needs replaced.

Pretty cheap to just replace the lube and gasket. Easy as pie, too.

Larry

jdr7785 · July 12, 2011

How long will lubing it up last? I took it to the dealer and they did it. I just dont want to be out a lot of money here soon since i just bought it

brainpause · July 12, 2011

How long will lubing it up last? I took it to the dealer and they did it. I just dont want to be out a lot of money here soon since i just bought it

50000 miles it more if it isn't damaged.

Larry

jdr7785 · July 12, 2011

ok just to be clear, the truck has 120,000 miles and your saying it should last 50,000 more by just replacing the lube?

txab · July 12, 2011

ok just to be clear, the truck has 120,000 miles and your saying it should last 50,000 more by just replacing the lube?

Just change it and run it until it lets go.

brainpause · July 13, 2011

ok just to be clear, the truck has 120,000 miles and your saying it should last 50,000 more by just replacing the lube?

Just change it and run it until it lets go.

What I meant was to change the G80 oil every 50000 miles. I agree too that you can just run it till it let's go afterwards. I wouldn't change out the rest end it gears until you've tried new lube in it either.

Larry

jro909 · July 13, 2011

the diff fluid is good for 100k unless your towing hard or working it like a mofo.....the g80 is pretty rugged

jdr7785 · July 13, 2011

Thank you guys! The lube seemed to work

Duelin · July 13, 2011

Thank you guys! The lube seemed to work

I would go back and tell "OTHER PEOPLE" that the lube worked and they didn't know what they were talking about. I wonder how much it would have cost you if you had listen to them?

jdr7785 · July 13, 2011

It was looking like it would have cost me over $1000. Glad it didn't

dlstewart01 · July 13, 2011

It was looking like it would have cost me over $1000. Glad it didn't

There is no additive needed for the G80 as some people think..

What GM says..

***Important: Installing any friction modifier causes the clutch pack in the locking differential to slip and miss engagement. A fluid flush can often remove debris that is a contributor to clutch chatter. Adding friction modifier additive can cause a loss of locking differential functionality***