Hey folks. Hoping someone can help me with this.
'98 v70xc
0 - 107k serviced at dealer only
107k - 163k who knows
163k I bought.

Has a vibration that can be felt in some minor amount at about any speed, or it's my imagination. Starting at 48mph and up until about 60-65mph it is extrememly noticable. 50 - 55 it vibrates horribly. Head rest on passenger seat reverb'ing like crazy from it.

-Due to other issues, I have just completed both front CV axles, both front wheel bearings, complete timing kit and serpentine belt.

After the above changes there was absolutely zero effect on the vibration. Not even a change in speed, rpm or anything else. Identical in nature.

-Had tires checked for knots/slipped belts, spun balanced and rotated. Front end aligned as well.

Again, after the above changes there was absolutely zero effect on the vibration. Not even a change in speed, rpm or anything else. Identical in nature.

-Checked all motor mounts by slightly raising motor to see if excessive movement in the mounts were had. None at all. All mounts appear fine. The driver's side strut tower has written on it "10/2007 replaced", but haven't a clue if one side or both (or either one!!)......both are identical in brand....German made. Struts have no popping / thumping to indicate a problem. Visual check of rear CV axles...boots are fully intact.

-On a road test I got on a downhill slope runing 50mph where the vibration is so awful. Pushed tranny into neutral and let the engine go back to an idle. Vibration never changed, even in the least. Seems to not be tranny or engine.

Here are my thoughts thus far.
-not the axles since old and new alike behaviour. Even if old and new were both out of balance they should exhibit SOME change in this vibration in speed starting/ending or severity. I would think.
-not wheel bearing,same reason as axles....new.
-not motor mounts. Engine at idle same vibration at 50mph.
-MAYBE not tires. All 4 could be faulty, but not identically. Rotation and balance should have at least changed the behaviour some what. I would think.

The only things I am left to think about are those things in rotation whether motor is rev'd or not.....rear CV's (look OK), rear wheel bearings (not a roar, but vibration??), or out of balance propeller shaft. I don't know enough about bevel gear to rule it out, but seems that tossing tranny into neutral "might" eliminate it, just not sure.

Ok, if your not tired of reading yet....

I COULD live with the vibration, but if it's origin has anything to do with a sealed/bearring'd attach point then something will eventually wear out.

What are all the thoughts out there? Just know your thoughts and suggestions are so very appreciated.

i read all the way and agree with your assumptions. but there is one that you haven't considered. was your volvo, to your knowledge, in any accident. and i mean a hard hit. if it still does this vibration, like you said, with the tranny in neutral, and your axles are new, then it has to be something that is affected by the rolling motion of your vehicle. i've never had a car do this, but an old motorcycle that i was considering in buying exhibited a similar thing while i was test driving it. the vibrations were so bad that the mirror almost spun all the way around, my hands went completely numb and i could see the front tire vibrating and hopping around. bikes usually have some vibration, even cars have some, they have to, but not like this. when i stopped to look at it, another older biker pulled up and asked what was wrong, when i explained the feeling, he just looked at me and said, the bike has been hit bad and no amount of pulling and stretching ain't goin' to get it straight. when i asked the seller, he admitted that it had been hit, but he swore on the proverbial stack of bibles that the bike was straight. i didn't buy it because as i was going home to think it over, i pulled into a body shop, bought the workers a case of beer and proceeded to ask them nine million questions and they told me that yes, to the naked eye it looks straight, but it might be off like a thousandth of an inch which would create this oscillation/vibration. over time it would have gottten to the point where the welds would have cracked and the bike would have literally fallen apart. sorry for the long post, but give it a shot. stop by and ask one of the workers or the owner. buy him a beer and pick his brain. you never know, they might take a look for nothing. good luck and keep us posted.

Well, good point. I had a CarFax on it and only one minor bump up to the left rear was supposedly ever had. Even the bumper scuff marks are still there. Not sure, but all paint seems original. I can't find any bondo with a magnet or such. But, there again, who knows for sure.

Thanks for the input though.

depending on the bump, it might have thrown something out whack. hope you find it. keep us posted as your experience might be useful to other members. good luck.

Well, dropping the prop shaft eliminated the vibration. Can't really tell if it is one of the cv's at each end or the carrier bearing, but the center U-joint "seems" tight and intact. Either way, Volvo factory is 875.00 and I wont' be paying that. If the car goes anohter 20k or so, to recoop my repair costs thus far, then I'll look into it.

For now the mpg should be slightly better running as FWD and so be it.

Thanks for the input guys.

try vandsautodismantlers.com for a used shaft. or fcpgroton.com for a new one.

hi, wow, these things are sensitive, i had a similar problem, in and out of volvo shop to find the reason for shaking, they did as you finally, dropped the middle shaft, but problem was still there, they noticed a tiny shake at one drive axle, the car had only 60k so they didnt think it was it, but anyway tryed a new one, voila, problem gone,