2002 V70 XC all wheel drive system.

[02V70]

I have a 2002 V70 XC that has a viscous coupling AWD system. I read that the AWD system breaks easily compared to Haldex. How can I tell if AWD is working? I don't hear any noises indicating bad bearings while driving. If it doesn't work, what needs to be replaced, and if it does, how can I service it to extend its life? I live in an area that gets decent snow in the winter and also like to drive on unmaintained dirt roads to go hiking and stuff, so AWD is useful.

[scot850]

If you have the viscous coupling unit at the rear of the prop-shaft, and that is bolted to the flange on the rear differential, then there are few things you can do. The actual V/C unit is not serviceable (well not on the older P80's it isn't), but the unit as a ball bearing roller at the the front. This bearing can fail and you may hear a rubbing noise particularly when turning left or right. If you are getting a clunk then the mounting bush at the front of the VC unit to the floor may have failed.

Prop-shaft: Again assuming it is the same as the older car, the center support bearing rubber can fail. On the older car it is not a serviceable thing for your typical DIY'r. Colorado Driveshaft have been the go-to for years on that for a full re-build which includes the front CV on the shaft as well.

Angle gear is next. There is no drain plug on that so the only way to change the oil (I know there are other brands), but for all you need I recommend you stick to Volvo's own fluid as it is formulated for the unit. Then check for leaks at the angle gear rear seal and if any oil is escaping from the RHS axle seals. The only other part is the angle gear collar. To access this you have to remove the angle gear (slightly easier than the transmission!) to check the splines on the angle gear shaft and on the inside of the collar. The collar is kind of a sacrificial part designed to strip the splines first to save the angle gear. However, if it has been bad for a while it will still ruin the angle gear splines.

At the rear then there is only the differential which again I don't know on the P2 cars, but on the P80 does not have a drain. Same process as the angle gear. Again stick to Volvo oil. Saving a few bucks on something that you may never change again does not make sense to me.

Hope that is of some help.

Neil.

[Blacklab467]

How many miles on this car? The first step is determining if it is still working or not. The best way to do this is to find some wet grass or a gravel alley and from a dead stop with the driver's door open or a trusted observer, accelerate away fairly hard. You should be able to see the rear wheels spinning trying to find traction. These vehicles spin the front tires very easily when the AWD is not working. A good test for the angle gear/ collar sleeve union is to grab the propshaft and see if it turns independently with the engine off, it shouldn't. You will have to jack the car up to do this test.
Maybe you will be pleasantly surprised to find that everything is working as it should.

[02V70]

My Volvo has almost 300k of mostly freeway miles. What is the difference between the propshaft and the driveshaft? Should the prop shaft be spinning independently of the other wheel or the driveshaft? Also, do both rear wheels need to be jacked up?

[XC70Rider]

My Volvo has almost 300k of mostly freeway miles. What is the difference between the propshaft and the driveshaft? Should the prop shaft be spinning independently of the other wheel or the driveshaft? Also, do both rear wheels need to be jacked up?

It is the same exact shaft connecting the front to rear differential. Some call it it the drive shaft while others call it the propeller shaft. No difference.

If you plan on putting it in drive while on jacks then all 4 wheels need to be evenly off the floor on secure jack stands. I've done that before to verify the AWD was working but I no longer need too. I can tell from acceleration and hill climbing if the AWD is engaging or not.