ok my blazer supposedly has a G80 but i have never noticed it locking up. I have been stuck a few time on the trails and i only get one wheel spinning.

1. how can i tell if its working
2. if it isn't working how can i fix it
3. is the G80 only in the rear or does it deal with the front diff too.

 

1. With the back end up in the air and the transmission in park, there should be quite a bit of resistance to spinning a wheel. This would be the preload on the differential.

2. Replace it with something better. Seriously, it is far too expensive to rebuild the G80 diff than it is worth. You would be much better served to get either an open diff carrier and install a lunchbox locker or get a limited slip diff.

3. The Gov-Loc (G80) is only in the rear end.

 

ok thanks