Rear Differntial Question
 

Hi i am new to the forum here but i need some help on this guys. So basically i have a 2004 Chevy silverado 1500 4.8L with the 4l60e trans and the 3.42 rear differential. my truck is a base model single cab two wheel drive that people like to call the one wheel peel. My rear differential has always confused me and i cannot figure it out myself. Like many people say a quick way to tell what type of diff you have is to jack it up and spin the wheels. Keep in mind my truck used to always be one wheel drive for the first year. now three years later it has been acting like it is a limited slip. When i have the rear wheels raised off the ground and i spin the tires the opposite side goes in the other direction as a lot of people say is an open diff. nowadays if i am stuck or in mud most of the time both tires will lock up and spin at the same speed as the other. If im one tire is on ice that tire will spin and the other will not. Well today i changed the fluid and found that it looks like a simple open differential. i just cant figure out why it acts like a limited slip on ice and a locker in mud or grass. if i do a burnout only onee tire spins. i cant seem to figure this out at all. My truck doesnt have any rpo codes that say g80 whatsoever and it is a 2wd base model pickup. there is no diff tag and none of the numbers on the diff itself lead me to any particular diff online to tell me what it is. anyone have any ideas ?

With enough power sent, open diffs will spin both.

Mine does on gravel, and mine does not have the g80. Mine has the z-71 rpo, but not that g80. I wonder if it was ordered specifically that way cause I was under the impression that z-71's came with the g80's.