Im not an expert, but if im not mistaken, there are 2 vaccum lines that lead from the transmission to the front differential under the passanger side, verify if they are connected. those lines engage your 4x4. regarding the whinning noise, if the lines are disconnected, your transmission is creating a vaccum and that may be the noise. that would be my first guess. that vaccum line engages the light also. If they are connecte, check to see if they lines arent plugged.
I dont know how much vaccum is required to engage it, but someone with a higher knowledge of this may be able to tell you.

 

i knew threads like this would come up... snow, and no 4wd, gotta love it. but to help ya out a little here... that whole whinning,,, are you shifting the truck while in neutral( i know it says shift on fly, blah da blah, but if you go from 2 to anything else. put it in neutral while free rolling just a litle, like 3-4mph, and it should take care of any noises, but that is because there are no sycros in the 231 transfer case...

but as for the light not coming on and not working, that sounds to me like vacuum, there are a set of vac lines on the passengers side of the motor, that lead down to the top of the transfer and then out to the front axle... somewehre in there there is a leak... check right at the passengers door, the lines run right past the cat and i have seen two trucks not including mine where thats where they melted...

 

thanks for the info, i just got done driving it and its all snow caked and sitting outside but ill pull it in the garage tommorow and look under it. i never shift on the fly with any vehicle. i alwasy put it in park or neutral or just leave it in drive while stopped and pop it into 4h. it just worked like a month ago. but i was in drive stopped when i heard the whining noise after i shifted around from 2h to 4h and back and forth because i noticed the light wasnt working. now before this happened when i was testing it like a month ago...it took a while for the light to come on. i had to move a ways until it came on. but how can u tell if ur 4wd works if ur light doesnt? maybe the guy who rebuilt my tranny forgot to plug soemthing back in

 

Hey man I just went through this whole thing use the search feature and type name. Don't even fix that vacuum crap listen to everyone and buy the posiloc tons on eBay

 

Search for the thread "No X4" just like that with the quotation marks. Will answer a lot of your questions.

 

i crawled under the truck and folowed the 2 silver hoses to the tranny, and the two cables wer unplugged. the red and black one. plugged those in and it works. plowed through a drift that i got stuck in 2wd. thanks for your help guys!!!

 

ok, and yes, i would suggest getting the posilock... its 202 with taxs and shipping... but i would deffinalty get one.. because i do have one...