So I am supposed to have the "automaticl locking differential". But It seems that It only spins one wheel like an open diff.
Do I need to change the fluid? Adjust it? WHat?

I am planning on changing the fluid anyway, What should I use and how much? thanks guys this is really frustrating

 

Look at the list of coded in the glovebox, if you see the nubers "G80" then you have locking rear differential. If it doesnt it is an open rear dif.

peace
Hog

 

hmm i sure hope it's fluid because if it isn't, it's busted. are those gears in the stock G80? It's not really that strong.

 

yeah i can atest to that had my g80 go out at 8000 miles. Only mods at that time was k&n fipk and hypertech tune.

 

my g80 is going strong at 75,000. jack the *** end of the truck up. spin one tire (by hand) and check that the oppisite is going the same direction. if it is your good to go.

 

The g80 does not lock above 25mph. I remember turning my wheels when they were jacked up and they went in opposite directions. That makes sense becasue it should act like an open diff when just sitting on jack stands. A good test would be to get on some grass and have a friends see if you spin both tires.

 

an open diff will spin both tires on grass. well from what i have seen. put it on dry pavment and do a small burnout. that is how i found mine to be locked up. that is funny cause my tires spin in the same direction. tear off the diff cover and do an inspection. that would be my next move.

 

I'd guess the only way to be 100% sure is pull the cover. My 02 HD is G80 and the wheels spin in different directions. I'm pretty sure the gov-lok is the only one that does that. All the other clutch type posi units I've owned the tires turn in the same direction when the wheels are off the ground.

 

One way to find out if your truck is equiped with a locking rear differential (G80) is by jacking up the rear of the truck and turning one tire really hard (by hand). The differential should "lock" making the other tire turn in the same direction. If you turn the tire slowly... the other tire will rotate in the opposite direction no matter what because it has not "locked". Thats why its called a locking differential.

For the lazy...
Just look for "G80" on the Regular Production Option (RPO) sticker inside the glovebox. If its there.....LUCKY!!! If no G80... a Limited Slip Differential is your best bet.

Hope this helps.

 

VERY WELL PUT