Or just hammer down on the accelerator, in 2wd, and see if both rear wheels pull or just one. easier to do on gravel or mud. :D

yea my spare tire is full sized it looks like the same one from when it was first put on the road

does off roading ruin your truck?

if you hit a rock or drown ur blazer in a mud hole it will, but if ur smart about it and dont try to be superman youll be fine just make sure you spray ur truck down good afterwards especially the under carriage be sure to get all or as much of the mud/dirt.sand etc off as possible.

ok ty what speeds should i go when going through trails

it really depends on the trails ur running and the capabilities of ur ride.

ok thanks

so i can rip it through water holes but be careful through ruts and rough country

Id just be careful everywhere... unless you are POSITIVE about the water wholes you are about to fly through. Take it from someone who's tried it, looks can be deceiving.

if u dont have a locker u can click your Ebrake down a few clicks enough to apply pressure on the locker and it will engage. i just did this last week cause my 4x4 is out.

Why not do what I did and just take it somewhere small and not too crazy first.
I'd never been offroading, so I didn't want to get too crazy. I headed down to a small mud pit that was recommended to me and just went through a few times. Nothing too crazy, but I got a feel for how the truck handles and rocks and whatnot. It's probably the best idea if you're new to offroading like me.
I stayed away from any large puddles that were there because I wasn't sure about them, and stayed away from any large rocks. The truck came out fine, and I had a hell of a lot of fun. lol