97' S-10 ZR2 4x4 prob!

[Redneck ZR2]

Recently I went muding with my buddies and I noticed that only my back tires were spinning meaning my 4x4 wasn't engaged but the 4hi light was on. However now when I push the button I hear the transfer case making noise that sounds like its engaging. but if I take it out and tune in a circle the truck has no wheel hop in the turn meaning its not working. Though with I push 4lo I will get the extra torque but still no wheel hop. Both lights light up. And when I look under the truck the front drive shaft is turning no matter what (not in four wheel drive.)

Any help is great!
Thank you

[OverBoardProject]

Simple one, your front axles are locked up with a vaccum pot located under your battery (I believe that's where it is on your truck but I might be wrong)

This is probably faulty. But check the vaccum line going to it first.

There are 2 choices if this is the problem, just replace the part with a stock one.
There is also a cable eliminator kit that gets rid of the weak link in the truck.
http://www.4x4posi-lok.com/
I have one of these units on my Blazer and think that it's great but overpriced.
You actually have a 2wd low range option using this unit, which I really like when backing up trailers.

[OverBoardProject]

I see that Posi-lok has a pretty good troubleshooting guide to your 4x4 system.
http://www.4x4posi-lok.com/PDFs/TSG_chevyT.pdf
They are of course trying to sell you their system, but that's your choice.

If you get their system look at the pictures closely when you install it, their directions are basicly useless. It should take about 1 hour

I can send you pics of what it looks like in my 85 Blazer if you want.