G80 always engaged in 4x4 HELP

**Madman** · 08-15-2009, 01:49 PM

my service 4wd light has been on for a while now and ive learned to ignore it because all the 4wd modes work without problems so after doing a bit of 2wd off roading i got back on the pavement and just wanted to test it out to make sure my g80 didnt take too much of a beating
in 2wd mode it engages when it is supposed to but when in 4wd hi OR lo regardless of speed or conditions
IT IS ALWAYS ENGAGED and will not disengage no matter what i do
the service 4wd light comes on during this and it drives fine but the g80 makes my tires dog walk or chirp on turns because it is engaged
im not sure what is wrong and i really need some help
im going to change all my fluids this weekend including the diff fluid
so i need all the help i can get with this problem
i also noticed that when i step on it in 4wd the truck tracks to the left a little bit but in 2wd it doesnt it is perfect

**MrShorty** · 08-15-2009, 11:36 PM

IT IS ALWAYS ENGAGED and will not disengage no matter what i do

There's no connection between the G80 and the 4wd system. The G80 shouldn't even engage unless/until one of the rear wheels spins. Just shifting into 4wd shouldn't engage the G80

...but the g80 makes my tires dog walk or chirp on turns because it is engaged...

Are you certain this is from the G80 being locked and not just from the transfer case being locked? If you put it up on jackstands, what does it do (only try this if you feel comfortable with what you are doing. I would hate for you to accidently drive your truck through your garage door). Just trying to make sure we are barking up the right tree before we get too deep into the diagnosis.

**bvogts25** · 08-15-2009, 11:44 PM

when the 4 wheel drive is engauged and you turn it always vibrates or "chatters"
i believe it is the differential that does this. and this is normal. i was curious about this (and kinda bored one day) and i got the manual out and it said this is normal. hope this helps...

**Madman** · 08-16-2009, 01:29 AM

thanks for the replies guys but
i wanted to make it clear that only the rear wheels chirp and hop on the pavement on tight turns as it does when the g80 sometimes get stuck while in 2wd mode
it is only the rear wheels so nothing to do with the transfer case

**azdrtdog** · 08-16-2009, 02:45 AM

Check that service light out the transf.control module will default to 4high on push button models if your g80 is hanging up its cause you romped it to hard in 2wheel.Ive popped a couple of em now and hard engagement starts to bind up the release

**CarpenterGuy** · 08-16-2009, 12:48 PM

the g80 engages by mechanical means only. putting it in 4 wd doesn't have anything to do with it. it will still engage in 2wd as well. i'm thinking you got the release mechanism jammed or something.

**Jimmiee** · 08-16-2009, 04:26 PM

Originally Posted by Madman

thanks for the replies guys but
i wanted to make it clear that only the rear wheels chirp and hop on the pavement on tight turns as it does when the g80 sometimes get stuck while in 2wd mode
it is only the rear wheels so nothing to do with the transfer case

On any conventional 4X4 when you lock the front to the rear <Full Time 4WD> something has to slip or bind unless both the front and rear differentials are going exactly the same speed. This will never happen in the real world because the road changes as do the tires rolling across it. This is the reason you CAN NOT drive a conventional 4X4 on the pavement. No problem in the dirt or slippery roads because the tires can and do slip.
Now if you do drive on the pavement in 4X4 something is going to bind and chirp the tires. Since the front tires have the weight of the engine sitting on them the rear tires are the ones that will hop and chirp. As others have said the G80 never comes into this picture at all.

**MrShorty** · 08-16-2009, 11:17 PM

If you are certain the problem is in the rear diff (as noted, I'm not fully convinced that it is), I would probably drain the fluid and see how it looks. Maybe it just needs some fresh fluid.