Background info: I have had a kind of whirring/sticking noise (kind of like using a lint roller on a shirt) coming from the driver side front wheel area for over a year now, but never had a problem with the 4wd not working other than when my solenoid was shot, but replaced that. The whirring noise has gotten progressively louder since i first bought the truck over a year ago, but its not overly loud, like you have to listen for it to hear it, but i do notice it alot more than when i first bought the truck. It occurs at all speeds and the noise gets faster the faster the truck is going. Not sure if this pertains to the problem but thought id mention it in case it was.

The problem: The other day before going offroading i tested out my 4wd and when i shifted (floor shifter) it into 4hi it went into 4hi, but when i went to shift it back to 2wd it stayed in 4hi. the light for 4hi went off, but i could clearly tell the truck was still in 4hi. I could shift from 4hi to 4low and i could tell that it was changing between the two but it would not go back to 2hi. i tried shifting from 2hi to 4hi and back a couple times and it still refused to go back to 2hi. i have come to find that if i shift into 2hi and shut the truck off and let it sit for about 5+ minutes that when i start it back up and drive off the truck is then in 2hi. When its in 4hi or low it works perfectly fine, and also when i do manage to get it back into 2hi it drives perfectly fine other than that whirring noise i mentioned above. Any ideas of what it might be would be much appreciated thanks!

 

Sounds like u might have a vaccum line issue.

 

The whirring noise could be the wheel bearing assembly needing replacement. If you jack the front of the truck up and see if there's any play in the wheel. If there's excessive movement side to side the wheel bearing assembly needs replacing.

In regards to the 4 wheel drive issue, as alsatropine mentioned it's most likely a vacuum line issue. Check your IWE. Check out this link on how the IWE works.