hi i have a 96 blazer an the 4x4 seems to be semi enguaged it seems to do this when im coming off the freeway an it makes a whinning noise.when it does that i would push the 4x4 hi then switch it back to 2wd an it would be fine. well now the switch will stay in 2wd an sometimes will not light up some 1 plz give me advice please an by the way this is my first post thanks guys

an is there any way to keep it from semi enguageing while drive or just keep it from enguageing at all

 

Does it do it under normal 2wd driving conditions? I have a 2004 that did the same thing. On the top front of the transfer case on the drivers side is a vacuum switch. The check ball inside gets stuck. If you have vacuum at the canister under the battery with the engine running, the vacuum switch is faulty. Its a pain the get to the canister. I had to take the head light out for the diagnosis. Maybe quicker just to take out the T/C switch & check the ball.

 

ok its under normal 2wd conditions. an if i get under the truck will i see the switch or will i see the t case motor i never done anything to a 4x4 car b4 so it would be nice if could see some pictures being the fact that i dont know what im looking at or for. an by it semi enguaging does that mean the t case motor is good or should i look into replaceing that .

 

Really hard to get a clear pic of the sensor or location. It will have 3-4 vacuum lines going to it. It is directly on top of the TC case on the drivers side closest to the frame rail. Most online parts stores will have a clear pic of the sensor for you. Your TC case should be OK. The noise your hearing is the front axles partially engaging due to the vacuum I think. The sound is real harsh, but mine still works just fine.

 

Here are some pics. Scroll down the page, you'll see some of the vacuum switch.

 

ok another question is, is there a way i can manually disenguage the 4x4 untill i get to a friends house to do this because i live in a apartment. an to get to the t case switch do i have to remove anything to get to it?

 

If you don't mind if air only comes out the dash vents, you could just disconnect the vacuum source line (under the hood) until you get it to your friend's house.

The vacuum switch is in a tight location, but I don't think you have to remove anything to get at it (done this 3 times in the past year, you would think I could remember....). Just lay down under the truck with your head under the driver's side door and your legs at the rear tire. Get a light under there, and you'll see where the 3 hoses connect to the vacuum switch. Takes a 7/8" wrench.

If you replace the switch, go with the GM part (89059420). The Dorman that most auto parts stores sell failed on me within about a year.

Also, if transmission fluid drips out of the vacuum lines after you take them off the switch, you really need to clean out those lines....

 

Ok so when i pull the vacuum hose off of the t/c switch it will disenguage the partical 4x4 enguagement an also when i do that do i have to remove the switch out of the t/c to drive it or just pull the hose an wait till i replace the switch

 

You can just pull the hoses; don't have to remove the switch. But keep in mind, it can get dirty under there. I'd probably get out some duct tape and cover the hoses and the top of the vacuum switch.

 

Heres my million dollar question. Will the 4x4 disenguage from being partially enguage

Anyone of you guys