Yesterday driving home in my '93 4Runner, there developed a noise like it was coming from front passenger side wheel. Chunking, clunking, grinding type noise. I engage 4WD and it goes away. I disengaged 4WD and it immediately returned. There has been a lot of snow/ice accumulation and cold as heck outside.

 

Crawl under it and take a look. Might have to pull the hub apart but I would crawl under a poor for freshly broken metal. CV axle? Front drive shaft? Might be worth changing the front diff fluid. If you do that just make sure you remove the fill plug before the drain plug. If you do this check for metal in the used fluid. A drain and fill is very easy. Just sucks to do in cold weather.

 

I took it out for some OTR diagnosis and realize it is not even engaging in 4WD, just the indication light on dash is showing that it is. Still when the 4wd shifter is in the 4wd hi or low the noise is gone. Damn shame.

 

Check to see what your t-case fluid looks and smells like.

 

Pulled it into the portable garage and the CV boot is torn, a round chunk of metal fell out when I pried off the boot.

 

Sounds like you got lucky. Just a new cv axle. Around $100 I I remember. While your at it maybe look in to the mod that you press/hammer the studs out of the diff flange and replace them with bolts. Quick search for CV axle replacement should pull that thread up. Good luck. Glad you found what appears to be the problem.

 

Thanks, should be cake.