Is my locking rear differential working?

[trail_turkey]

First off, I am not a mechanic nor am I well versed in technical drivetrain speak so please pardon any miss steps in this post. I did attempt to search this item and I'm sure its burried in the forum someplace but I could not dig it out. Sorry it this is a repost of common info.

 

Background:

I have a 03 Silverado with a tow package. I've checked both the original sticker options and did I VIN search and I'm convinced I do have a G80 locking rear differential on this truck. I've got 150k on all original equipment. I am the second owner. The first was my father so I know the history of this truck pretty well. It was not abused or overloaded.

 

Problem:

On a couple of occasions I have gotten "stuck" in situations where I think the locking diff should have gotten me out. Once was in a friends yard on a very level yard in WET GRASS. Another time was in loose gravel with the front ties in a very small rut. In both cases, one wheel was spinning and the other did not. In both cases I had no weight in the rear end. In the second case a guy in an F150 pulled me out. Very embarrassing.

 

Question:

Is the G80 rear end functioning correctly given what I experienced? How can I test to see if its working properly?

 

Additional info: Earlier this year (after the two experinces I had above) I had to replace the rear differential cover due to corrosion. When I did I was very carefull to get the proper replacement fluid so I know I have the right stuff in there now. Its "possible" I had the wrong stuff in before. Hard to tell as its a used truck.

 

Thank you in advance for any information you guys can provide.

[Stephenspann27]

The locker should engage at speeds below 20mph, above that it will disengage. There are videos on youtube you can watch to see one in action. Most people hate the G80 locker because it is known to grenade or be unreliable. I have a Z71 Tahoe that has one. The more offroading I do the more it seems to make strange noises when engaging/disengaging. I feel like it is on burrowed time. I plan to replace it with an Aussie locker.

[jaredlucky16]

G80's are junk see way to many issues with them

[kstruckcountry]

If both wheels aren't spinning it's not working.

 

I like mine a lot. Works really well for low speed crawling on slick rocks or up steep gravel.

[Mckenzie]

G80's are not junk... and to test it find a small ditch and hit it diagonally so that it is flexing aka one side of the rear end is trying to come off the ground and the other is being squished or has all the weight on that side. Give it some gas and let it spin a little and you should feel the locker kick in and you'll be able to crawl right out

[jaredlucky16]

Junk

[00Silverado4x4]

Nearly 100k miles and mine is still working great. Last truck had 54k miles when I traded and the G80 was still working good too. Love the feature and when I buy my next truck...no time soon...I have every intention to have the G80 option in it.

[Mckenzie]

206,000 miles and many burnouts latter and its still doing good

[jaredlucky16]

Ever seen one after they grenade. It gets expensive quick. The seem to be very unreliable too when it comes to locking

[Silverado4x4]

Most people when they get stuck and one wheel is spinning they nail the gas but with a locker you have to give the gas lightly and let one wheel spin below 20mph and then the other wheel will lock.

 

BTW did you check the tag inside the glovebox? If you have one it will say G80 among all the other numbers listed. If you dont see it then you dont.

[Axel114]

_{The E-80 is made by Eaton which has been making rears and tranies for big trucks for years.I would think they can make a rear for a pick up truck that will last.I have a 2011 silverado and in the owners manual it tells you if you are going off road "and high wheel spin is required" to turn off the stability control and traction control.I don't if a 2003 has SC and TC. I all so would agree with Silverado4X4}

[trail_turkey]

Thanks for the info guys. I'll have to try to test it out as you've suggested. I don't stress it too much so I'm not to concerned about it exploding.

[Z45]

G80 was an extra cost option back in 03 and was never included with any option package. If you do not have the G80 code on the option label in the glove box, you do not have a G80. If you had the rear cover off you should have been able to see the G80 and looks like this.

 

From what you descibe its does not sound like you have the G80 in that truck but look for the option code.

 

I have owned 7 GM trucks with a G80, plowed snow, towed trailers, off-roaded (not to beat on it) and never once had any issue with it. The ones that claim to have issues are those that modify the trucks and the G80 is being used for what it was never designed for; over size tires, suspension lifts, severe off-road abuse and the like. 99% of the time when something grenades it was being abused way past what it was designed to endure. Remember, when something breaks on the truck its never the drivers fault, its always someone elses.

[KMGZ400]

^^^ is right.. you say your convinced you have a G80? its either you do or your dont. if you checked the vin, did it say G80 or not? check your glovebox code. does it say G80 or not?

 

i have a 2003 silverado Z71 that does not have a G80.

 

 

also, the G80 is designed for on road use and light off roading. it is not meant to do burnouts or extreme offroading or anything like that. its meant for a stock height vehicle with stock tire size. its does its job well. is it the best? no. to be honest its not common to hear of a G80 grenading anyway

[spankrz]

do a good burnout, and post a pic of the result on the pavement. we will let you know if you have a g80.