I have a 96 Blazer 4x4 with the 3 button switch. Recently I've been hearing a grinding / rubbing noise coming from the front passenger side wheel. The noise is ONLY heard while the truck is in 2wd. However when I put the truck in 4hi or 4lo the noise completely goes away. Today I decided to jack my truck up to get all 4 wheels off the ground to test out the 4wd. I can hear the 4hi & 4lo engage. I can also see the drive shaft spinning when the truck is in 4x4 when someone hits the gas. However the 2 front wheels will NOT spin. I was told it could be a bad passenger side wheel hub assembly. But why would it only make the grinding noise in 2wd & not 4wd? Any suggestions on where I can look? I tested the dash switch in my friends Blazer & it worked fine. Thanks!

 

If you look in the forum you'll see a DIY section https://blazerforum.com/forum/tech-a...e-first-30093/ <----

if you look in there you'll see a wealth of information on any topic or problem you'll likely come across, I recommend taking a read through there........

However, I'll make you're life easy this time https://blazerforum.com/forum/tech-a...ill-help-7180/

 

Thanks for the links! I will be looking into that today. One more question though. Can a bad passenger wheel bearing cause the 4x4 not to work at all?

 

NO.

It's most likely the vacuum switch on the transfer case. There's a spring loaded ball that gets pushed in when you select 4WD. It's either sticking or stuck allowing the right axle clutch to partially engage in 2WD causing the grinding noise.



It's located on the driver side of the transfer case, just inboard of the driveshaft yoke and has 3 vacuum lines attached to it. Dorman makes the part (#600-500) and it's also available in their "HELP" line of parts (#49315). It's under $20, most parts stores keep them in stock. It takes about 15 minutes to replace it.