How to diagnose a bad VC on 1998 xc70

[JasonVolvoMan]

I just put in a brand new awd shaft from Colorado driveshaft. Every time I back up I get a bump noise from the rear of the car. I guess that's a natural thing from what people have told me on the forum that I have asked. Now I am getting a bump sometimes when I start to move forward too. On the highway at 75mph it feels great. No noise or vibration. Today we are having a blizzard here in Connecticut, so I will defiantly put it to the test later today. I also have 4 same size tread brand new tires and just got a front and rear alignment before I put the shaft in. Anything I can check for to see if the VC or bevel gear are bad. I mean it seems fine but I just want to wreck my new shaft

[Ozark Lee]

A bad Viscous Coupler or a bad Bevel Gear won't hurt your new prop shaft unless they literally seize up and come apart. They will start to make very significant "bad" noises well before they explode.

My only AWD came without a prop shaft and all I have is a replacement, junk yard, shaft on the floor in the garage, waiting for its vacation in Colorado. As such, I really don't know what a bad coupler or gear would sound line or behave like.

I know that was of little help to you but you can at least rest assured that your prop shaft isn't in imminent peril.

...Lee