My 97 4runner (4wd) is making a lot of noise in the front end. It seemed to me to be the lt front wheel bearing. I has a low rise lift at my shop, and in turn the front wheels by hand, the lt was hard to turn while the rt was nice and smooth. I removed the the knuckle, and had a local shop press in a new bear for me. Put it back together, still have a noise. Like a grinding/scraping noise. The brakes are new, no signs of any problem there. I did notice that the front drive shaft turns when I have it in 2wd. Should that happen. There is a vacuum control on the front diff, maybe it's not releasing? Not quite sure what to try next........

 

Drive shaft should not spin. Is the suspension fully drooped when you're trying to spin the wheels?

 

Yes, all 4 wheels 3ft off the ground. I can spin the rt front freely, that one spins nice. When I spun the lt front wheel, It felt rough, and the the front drive shaft did spin...I turned the lt hub when I had the knuckle off the truck, and it did not spin very easily, so I thought the wheel bearing was the problem. Now I'm thinking the cv shaft or the front diff. There is a vacuum servo on the front diff, so is that what is supposed to disconnect the front drive shaft?

 

fully drooped suspension might be maxing out the cv shaft, does it spin better if you jack it up from the suspension arm so the suspension doesnt droop out?

 

I put it back on the ground and drove it home. Whirring sound at normal driving speeds, when going slowing- like at a stop sign, then there's a grinding/ scraping sound.

 

Looked at it again. It's the differential. I've got a used one coming.