the filler holes are under the truck on the transfer case. there is one up high and one lower. obviously the higher one is your filler hole.

 

If you have a vaccum problem, the blend doors for the heat & A/C won't work, & your front axle will not be "connected" to the front drive shaft.

The test I outlined a page or so back was poorly worded, & most likely confused you rather than helped - let me try again:

When you get the front end in the air, in 4x4, key on not running (but run for just a minute prior to build vacuum), one of the front wheels should not turn - & if you turn that wheel forward & backward, you should hear it clank slightly in the differential, and see the front drive shaft move just a fraction of an inch.

Basically the T-case engages the drive shaft, but vacuum engages the driveshaft to the front diff & front wheels.

Hope that's better!

 

oh ok, i see what you mean now, and you said the blend doors for the ac wont work, did you mean that say if i turned the **** to feet only or head only it wouldn't change where the air comes out?

 

Driving goes a long way as well. I would start with tires, but mine did an OK job with highway tires in my initial tests. I'd check to make sure the 4wd is engaged if you didn't notice front tires spinning while you were stuck. You can test it by trying to break the tires loose with someone watching on loose or slick ground....Or the smart way. You can check under your battery to see if the vacuum actuator is holding it's vacuum. This is the usual culprit. Any videos?

 

i have a 96 2 door blazer wit Firestone destination A/T's and an open rear diff, and i keep right up with a CJ, with a 2 inch lift "D

 

This thread is ancient; but since you dug it up:
a limited-slip diff is specifically designed for better ON-ROAD travel.

An open is way better then a limited slip for off-road, but you need to know how to use it.

waddle, waddle, waddle, with a bit of controlled breaking to spread/shift the power distribution to your tires. For the record I love my open, way better then the LS POS g80 i had.

However for rock crawling/mud, a locker is great, but for all around trail goodness, short of an actuated locker, the open is king.

 

I have an 01 Blazer LT and i'm having trouble with my 4wd. i've followed what it says to do for putting it into 4wd. it says that the light indicating that its in 4L should stop blinking after 30 seconds but it never does. could it just be a faulty switch or is something actually wrong with my 4wd? and how can i check to see if the 4wd is actually engaged or not?