so i have been battling with my four wheel drive for over a year now. When i first got my blazer (95) im pretty sure it didnt work. I had to replace the button box (whatever its called?) on my dash, then i had to replace the decoder motor. But sometimes when im driving, mainly at high speeds, for some reason there is this terrible grinding sound, and when i hit the 4wd hi button, it goes away, but is in 4wd. when i try and shift back to 2, the button says its in 2 but you can tell its still in 4, and the grinding comes back. its like it wont stay in a particular range and is confused. has anyone else experienced this problem? any suggestions? thanks.

 

Grinding ??? Do you mean a vibration ? Maybe coming from the transfer case or U-joints perhaps ?

Also, do you mean the grinding won't stay in a particular range ??

 

no, not so much a vibration more of like a whining grinding sound, its hard to explain but it sounds like gears not full engaged or disengaged. and its only when i switch from 4 hi to 2wd. It wont completely disengage because i can feel it still in 4 hi when i turn etc.

 

It feeling like its not disengaging is normal I believe, my Sonoma does that, and my blazer did as well.

As for the grinding, I had a similar issue when heading to the shore for the concert, sounds like a grinding noise, like a airplane something, was the wheel hub if I remember correctly. Could be a bearing too, I can't remember which I replaced.

 

I too am having this same issue. From my research it is related back to the vaccum ball in the drivers side fender or the actuator under the battery... I'll try and find the thread(s) that supported these things and report back.

BTW, It's better described as something like an ABS engagement sound along with a whine sound. But this will go away after engaging 4hi (immediately) and will sometimes return (lately everytime almost ) after engaging 2hi. After playing with it several times it will stop.

To the OP try turning the wheel all the way to the left and backing up. I discovered this "fix" while back down and out of my driveway. The truck rolled easier immedately.

EDIT #2: Links to others with problem. I searched " grinding noise"

https://blazerforum.com/forum/showth...grinding+noise

https://blazerforum.com/forum/showth...grinding+noise