4x4 rear axle not locked up
 

its just a quick question and im not sure about it.....

i had the car jacked up today on 4 jack-stands and was putting on a new trailer plug. before i put it back on the ground i decided to make sure that the 4-wheel drive was working among checking some other things. anyway, i got in the car and started, put it in gear (2hi) and both rear tires spin. (G80) brought everything to a stop and put it in 4-lo, both front wheels spin and only the driver side rear spin. same thing when it was in 4-hi.
so my question is:
why doesnt the rear end lock up when in 4x4? or is it because there isnt a load on it and it is getting a different amount of power?

bump! im just curious!

its still an open diff, you dont have lockers

so how do you figure out if you have a gov-loc, limited slip or a locker when they all have the same G80 RPO code? its driving me crazy. i was under the car yesterday and the PO serviced the rear end and if there was a tag on the diff cover, there isnt one anymore. so how do i figure it out?

The G80 is only the rear end option. I know of no GM that offers a locking or limited slip front end. You have to do that yourself for around $600. 4x4s are really only 2 wheel drives without the G80 option. One front & one rear wheel pull in 4x4 mode. With the limited slip you have 3 wheels working.
Hope this helps

alright, i have a G80 rear end but i dont know whats what?! Gov-lock or Limited slip. i was wondering how to tell the difference. and why does the rear end spin both tires when in 2hi but only the driver side when in 4hi/4lo? thats my big question. and if someone would be kind enough to possibly supply some pictures of the gov-lock and a limited slip so that i can see the difference.

TIA!

(thanks in advance)

With the whole car on the ground just jack up one rest wheel and try to turn it. If it doesn't turn you have a limited slip. If it does its open.

The gov-lock is GM's version of a limited slip. However, it isn't truly a limited slip set up. A true limited slip will actively move torque to the wheel that has traction. Whereas the G80 (gov-lock) will effectively lock both rear axle shaft together much like a locker, which is why they tend to explode under extreme stress. However, the G80 will only lock under certain circumstances that you can read about through the link provided by coolasice.

thanks Red. since i asked the original question i have done a lot of research and seen some videos on the the whole gov-loc thing. i finally get it now.

when i had the truck on jack stands and put it in 4hi and went to see if both rear tires were spinning i had noticed that it was only doing about 5mph or so. i didnt do the math or anything but i figured that is why it didnt lock up. didnt have enough wheel speed difference or not enough torque to lock them. when it was in 2hi it was doing about 15-20mph when i got out to look, and both rears where spinning.

i still dont get how a limited slip can move torque from one wheel to the other, but i dont have the internet and shall soon find that out. all i know is that my G80 is working correctly as of right now. (with a good little burn out to prove it) maybe some day i might get adventurous and put some eLockers/Air Lockers in front and rear....but thats a long ways away!