Ok my blazer has a push button 4wd setup. When i push the 4wd button i can hear my transfer case dropping into 4wd but my 4wd does not work. When it is not in 4wd i can climb under my truck and turn the drive shaft that goes to the front pumpkin by hand, when i push the button I cannot. To me this does not sound like a problem with my transfer case but with the front differential. Is there any common problems with this I should check for?

 

What year is the blazer?

 

Sounds like the actuator on the front axle, early models used a vacum type and newer ones are electric.

 

yeah i would say it is the actuator, i had a 93 that used vacum and that went bad

 

FYI my blazer is a 1993, 4.3 vortec. I have been narrowing down the problem area today. I have vacum, the diaphram under the battery tray works, the cable is fine. Its the pin that goes into the front differential. Seems to me that pin is suppose to pull out about an inch or two to engage the 4wd, it does not, it moves back and fourth about a 16th of an inch which im sure is not nearly enough. Any tips, secrets, or direction on what to do next?

Im not sure what is on the other side of the pin, never taken a front diff apart before, but im extremely good with mechanics and will pull that bad boy out if I have to.

 

I believe it's held on there with 4 bolts, pul it off and see if the diaphram works or if it's a probem with the fork or coupler on the axle.

 

I did pull it off, everything seems to work correctly until I get to the rod that actually stick out of the front pumpkin. The rod does not pull out more than a 16th of an inch. Looks to me like it has to come out an inch or two before it will let the 4wd engage. Whats on the other side of the rod inside the diff? Im thinking thats where my problem is. Is there any notorious problems there or do I get a random new problem???

 

Check out this link, it shows a diagram that will help you.
http://images.google.com/imgres?imgu...a%3DN%26um%3D1

 

Problem solved. I bought this truck from a guy who considered himself a mechanic... LOL. There was a shim/washer inside the pumpkin preventing the fork from sliding in and out of 4wd. Replaced the shim and put it in the right spot and now once again it is working beautifully. Thatnks for the diagram it was very helpful.

 

No problem, I'm glad you got it working.