Hey, new to the forum, just picked up my first volvo about a month ago. Absolutely loved the car until the first snow today in which I realized the awd seems to be having issues. Only happens from what I can tell after the awd tries to engage. Kinda has a clicking/clanking sometimes grinding noise proportional to speed, definitely drivetrain, still there when the engine is disengaged. Seems to be coming from right under the center console/center dash area. Also it doesn't seem like the rear wheels are getting power at all when the front ones slip, and this is when the noise kinda starts. And it doesn't seem to be related, but when the front tires slip the front left makes a grinding/buzzing noise but only after a second or two of slipping. From what I've read it sounds like it could be the bevel gear or driveshaft? Any input would be appreciated, I really like the car but would love to repair the awd function for snowy Minnesota winters as opposed to just pulling the driveshaft out...

 

Check the center bearing on the driveshaft. They are not replacement items so check out rebuilt driveshafts from Colorado Driveshaft.

 

If the car has traction control it could be making the strange noises you are describing. If that's the case, you may NOT have a problem at all. Also, I believe that AWD system is ALWAYS engaged, or should I say active.

 

rspi - that's a good point I didn't think about it as far as the front left tire, but the other issue is definitely not normal, and trying to crawl up a hill that had some snow on it I could get the front tires spinning but the rears didn't seem to engage, thats why I'm guessing the awd isnt working. Would the bearing be an issue that could not allow awd to engage, or would it just make things really noisy? any suggestions on how to diagnose this, I dont have any jack stands or anythign to lift all 4 tires (unless I go buy some today), but I do have a pari of ramps I may get the car up on to take a look at the bearing

 

upon further inspection today, the horrible noise (as of sticking something into a fan, or a heat shield resting on a driveshaft) appeared to have been my heat sheild that sits over the cat resting on my driveshaft... the shield had fallen apart so much around both nuts that hold the right side up that it had just fallen down, probably got ripped down after the first snow (it was pretty substantial). After some homemade "washers" that noise is no longer evident. There isn't much (read; any) snow on the roads anymore for me to test out with some donuts but I'm still skeptical to if the awd is working... viscous coupling in the rear now possibly the culprit? Also, I have now noticed a (excuse my descriptive inability) "pulsating, whining sound" that seems to be on for 1 second, off for 1 second, on, etc... (pulsating being that it pulsates while on for the 1 second). This is proportional to speed and goes away with the tranny in neutral. driveshaft bearing still? The driveshaft appeared to be pretty good for a car with 187k miles, but maybe this is what it is? But I'm done crawling around under the car on the wet garage floor for today, its cold out and there's football on tv. Thanks for the help all

 

Now the noise seems to be evident with the transmission engaged or not, any thought? I'm thinking wheel bearing, maybe driveshaft bearing?

 

So I jacked up the rear of the car today, I can spin the rear wheels and the driveshaft spins (in park) but if I grab onto the driveshaft I can hold it still while the tires still spin. Should the driveshaft not be able to spin when the car is in park?