Discussion in 'GM Powertrain' started by unplugged, Apr 24, 2008.
what years did they come in.
I want to remember they offered a variant of the G80 since the 70s??
Yeah, the G80 is by far the best factory offered diff on the market.
It's bad rap for "blowing up" is almost entirely undeserved and caused by people just plain abusing it. For example, laying into the accelerator in a one wheel, low traction condition, causing the diff to engage extremely hard.
Though the biggest killer is non-stock, big tire, off road use where it is subjected to torques well outside it's design range.
Even then I have to wonder what people are doing to them.
My own truck has it's original G80 with very high mileage on it and even though it's now facing HP and Torque numbers way higher than stock, it's last inspection showed it to be in mint condition.
In bad weather, I wouldn't want anything else. In fact in many conditions a 2wd GM with a G80 handles better than a competitor in 4wd.
In the snow it's like a damn snowmobile.
Thanks for the heads up
Thanks for the heads up!
I would Add the Following Information for Those Who Have the G80 in their Trucks and for Those Who just Bought a Silverado/Sierra, and it Has the G80, Its Regarding the Servicing of the Factory G80....
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.
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.
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.
Thanks 99Heartbeat for this info. It is really good to know.
Another alternative to the additive is simply using Mobil 1 gear oil in it - no additive needed in this case.
Ya know, that's a confused topic, Mobile 1 has some additives and we have a few threads that discuss it.
My personal thoughts are that Mobile 1 is ok, just don't add any more.
There are other synthetic alternatives out there, but none that I've been willing to recommend. Mobil 1 or OEM oil with the additive is as far as I will go. I've trusted Mobil1 in all my G80 rears for a couple decades and it's not failed me. I don't vary, though.
I think I said that Mobile 1 should be ok to use; yes, it has additives, but I suspect not enough to cause any problems.
I use Royal Purple, it may have additives as well.
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