hey guys my truck recently doesn't stay engaged in 4x4 mode... its a '91 s10 blazer 4.3L... Anyhow when i put it in 4x4 mode with the shifter on the floor i see the lights turn on to show engaged... When i start driving and give it gas the light turns off which tells me it not in four wheel anymore... Any ideas?

Aztec

 

Sounds like the vacuum system isn't sealed up properly.

This thread should shed some light on the subject:
Common 4x4 Problems

 

I see the vacuum hose go underneath the battery tray but where is the other end of the vacuum hose located at and is it visible if i crawl under?

 

the vacuum line that goes from the vacuum shifter under the battery tray goes to a vacuum switch on the transfer case. More then likely your problem will be around the vacuum switch(they are known for going bad). There will be three vacuum lines that go to the switch connected by a boot (that goes on only one way). The switch is located on top of the transfer case so your gonna have to reach up there and feel around.

 

Thor_449 thanks for the reply... now if i can get off my lazy *** to check it out i will got on that... Thanks for the info and i'll holla at you if that was the problem!

Aztec