[19trax95]

It won't be GT. It will be most likely GU6 which is 3.42.

But here are the codes to check anyway. Look for the ones that begin with "G"

GU4= 3.08
GU5= 3.23
GU6= 3.42
GT4= 3.73
GT5= 4.10
G80= LOCKING DIFF

 

[19trax95]

The traction control on these trucks makes them practically useless off road if you get stuck.

My father's 09 literally would not let the wheels spin when I got stuck in snow. I had it in 4 hi and foot to the floor and it would spin the wheels for a split second then cut all engine power so it was just idling. You can't even shut it fully off when you press and hold the button to "disable" stabilitrac and traction control. Only way is to put it in 4 lo or pull the fuse.

As for the oil, no, do not put any additives in there. It just takes regular 75w90 gear oil. You'll likely notice most of the name brand gear oils say limited slip on them. I've used mobile 1 and valvoline in several trucks with the G80 and haven't had any issues. As long as you don't add any more you'll be fine.