Roar from Right Front

I have a 96 LT with 84,000 miles. Not long ago I heard a loud nise from right front and was told it was the wheel bearing. As you all know, being 4WD I had to buy the whole hub, not a major problem. Pretty easy to replace. Now the sound is back and it seems the only way to stop it is to pull over, switch to 4WD, move forward a bit and then go back to 2WD. Could this be a vacuum problem because it seems to happen about every time I move the heater controls on the dash. Checked the ball under the hood and the lines look fine. Other than leaving the controls alone what should I look for? Any Advice would be GREATLY APPRECIATED!!!!!!!!!!!!!!!

Could very well be vacuum related.

Search this forum for "vacuum switch" or "4WD vaccuum". There are a few threads that go into it.

Sounds like the 4x4 is acuating when it shouldn't.

It goes completely away when you switch the 4x4 back and forth?

Also, what brand of hub did you install?

As a test pull the main vac line that goes down to the vac switch on the top of the xfer case and plug it (golf T works well)ff under hood - does that fix it? If yes you have a problem there. If no, look at other items like CV axles and sorry, a process of searching and listening. Blazers have looks of parts that act up with age and can make noise.

I don't really remember what brand, but yes it goes away when I switch back and forth until the next time the dash controls for the heat are adjusted. Really aggravating at times.

Start the truck and ljack up the front right and see if you can spin the tire. If you can't it's in 4x4 all the time.

I had this problem because the switch on the transfer case failed in the open position.

Start the truck and ljack up the front right and see if you can spin the tire. If you can't it's in 4x4 all the time.

I had this problem because the switch on the transfer case failed in the open position.

Good idea.