After many loyal years of service by my 850, I switched to a 1998 Volvo V70XC last fall. I love this car - and am not sure I ever spun a tire through a rather harsh Maine winter. About two weeks ago I mounted on my summer tires and noticed a strong vibration at 25 mph. I rotated the tires last weekend and the sound persisted - so I just had four new tires mounted and balanced as well as a four wheel alignment. Although my wallet is significantly lighter - the noise is still there.

Having grown up and cut my teeth on only the front wheel models - I have very little experience with the things that make my back wheels turn. I am researching u-joints, bevel gears and viscous couplings - and am hoping someone has some advice on how best to proceed.

This site is amazing!! Thank you to all who offered up suggestions - and I wanted to update you on the diagnosis.

Finally put the car up on the lift this weekend. The u-joint was worn - but was not an obvious source of the issue. After getting the vehicle up to 25 mph you could see the shaft begin to flop near the center bearing. Upon closer inspection it became clear that there was a small rip in the rubber boot on the center bearing support.

I'm not sure, like the chicken and the egg, if the tear in the boot is causing the wear on the u-joint, or if the u-joint caused the tear in the boot. Regardless, I am now a member of the front wheel drive club and will spend the summer deciding if I should rebuild the shaft using the FCP Groton kit, or perhaps will just order a remanufactured shaft.

For anyone seeking to remove their shaft you will need a 12mm socket to remove the center bearing support, and a 6mm allen wrench to remove the bolts at either end of the shaft. Removing the enter center bearing/exhaust support plate makes things go a lot smoother. As does having an impact gun for the allen bolts so you can keep the car in neutral to rotate the shaft.

Thanks again.

You might want to read this 2003 post:

http://www.brickboard.com/AWD/volvo/592388/V70/awd_owners_drive_shaft_center_bearing_viscous_coupler_bearings.html

I couldn't find it, but someone took a center support bearing for a 740 and fitted it to his 1998 AWD. Cost: $40.

Klaus
--
Always willing to listen, just not able to take direction.

The 98-02 cars are known to develop a shudder in the rear when cornering sharply and a slow speed - I suspect the diff is not unlocking in that instance and the viscous coupling is also a little to blame. But that doesn't sound like your problem.

Because you cannot rotate the wheels unless all 4 are off the ground, re-visit the tire store and ask for a favor. Lift the car enough to see under the car with someone in the driver's seat. Put the car in gear and sloooowly get the speed up to 25mph while you watch the prop shaft and the rear axles.

You are looking for slop in the front of the prop shaft where it connects to the bevel gear, the center bearing, and both axles.

The front propshaft CV joint is easy to replace. The center bearing is hard, but can be done. One of the posters here replaced his with one from a 745.

Klaus
--
Always willing to listen, just not able to take direction.

Thanks Klaus - I always appreciate your insights! I had discounted the CV joint because it was only occurring at a specific speed rather than changing in tone or frequency. I am friends with my local mechanic whom I can swap Volvo advice for favors (such as time on his lift).

If this proves to be the source I may pull the prop shaft and reap the rewards of having a broken car, but increased MPG's for the summer. Has anyone had luck with any source other than the dealer for these parts?

Before you pull the propshaft, put the car in 1st gear (or 2nd) and see if the problem is not rpm sensitive- might be a broken engine mount??

If you pull the prop shaft, mark all of the joins with paint so you can put it back together nicely and not out of balance. Someone told me that different bolt sizes were used to balance the shaft (highly unlikely), so watch out.

The front CV joint is not terribly expensive, but call Tacsa Volvo for the best prices. A dealer will only replace the entire shaft rather than 'repair' the center support bearing, if it needs to be replaced. Someone here replaced his with a 740 center bearing.

There is an outfit in Denver that does driveshafts, cheaper than the dealer but still more than $50 for a 740 bearing.

Driving without the propshaft will let you feel torque steer, but the mpg will go up to make up for it.

Klaus

--
Always willing to listen, just not able to take direction.

the way you can tell if the bolts have been used to help balance the prop shaft is the length.

We're talking about the six bolts in the CV joints at each end of the prop shaft. If any of the bolts is longer or shorter than the others, that is the clue. If your bolts are not all the same length you MUST put them all back in the same place. EXACTLY the same bolt in EXACTLY the same bolt hole.

When I pulled my prop shaft the first time I marked it with paint but I didn't do a very good job and most of it came off. I don't think the orientation of the prop shaft to the bevel gear or rear diff is really important. I think where it's really important is if you split the prop shaft at the center u-joint - then you really want to be careful to keep the two halves oriented in the same position when you put it all back together. Someone with more driveline experience might correct me on this though - I didn't have any problems with mine though.


I think the front and rear CV joints /are/ actually pretty expensive - currently $289 at FCP. The good news is that they are serviceable and you SHOULD service yours TODAY. Get some CV grease from your local parts place and make sure it's CV grease with Moly and not regular wheel bearing grease. You can pop the top covers off the joint pretty easy and then clean up all the dried up grease inside as best you can, and then pack the new grease in and work it all around the ball bearings. It's not tough, though time consuming and messy. I think I saw a writeup on this on matthewsvolvosite.

I replaced my center carrier bearing and bushing with that from a 7xx. You have to shim the exhaust hanger/bearing mount down away from the car a bit as the 7xx bushing is a bit taller than the one from the AWD cars. Two or three washers is all I am using. Also you'll need a new bearing that fits properly. I used a SKF 6206-2RS1n for mine but I can't guarantee that it will fit for you so you'll have to measure.

The torque steer is annoying but the power increase is plenty nice.

Also FWIW I have removed my prop shaft again for the summer (mpgs, power, also I want to do some work on the center carrier bushing) and found the main bushing for the 'torque tube' is moving and needs to be replaced... probably part of the 'thumping in tight turns' thing...

--
1998 V70 AWD->FWD->AWD Turbo 215k+

Tasca Volvo lists the front CV - 30614441 - at $214 plus shipping of course.

Remember, your local dealer will NOT refurbish the center bearing, they only replace the entire propshaft for a LOT of money.

It is very difficult to raise all 4 wheels off the ground, even if you have ramps and jack stands. With the car only off the ground a foot or so, leveraging the prop shaft out from under the car and placing it back can be most hurtful to your shoulders :>)

I haven't done it. I should repack both CV joints, but I dislike lying underneath my car, and the local garages that I would trust to do the work charge $115/hr for labor. Like replacing an axle instead of replacing a CV boot on one of the wheels, it is cheaper to just replace than pay $115-120 for a repacking.

Klaus
--
Always willing to listen, just not able to take direction.

good price on that joint from Tasca. Thanks.

You actually only need to life the passenger side to take the prop shaft out, and it's really not as bad a job as you would think. Summer is the time to do it of course when it's warm out and you can take your time.

--
1998 V70 AWD->FWD->AWD Turbo 215k+

Hello, The time honored red flag is that a strong vibration throughout the car points to the driveshaft. Your post made it sound like the vibration began immediately upon mounting the Summer shoes. Remove each wheel and rotate the hub, feeling for roughness. Removing the driveshaft would be conclusive. You could drive the car while your driveshaft was being repaired or a new one delivered. I've read they're about a $K. How to zero in on the bevel gear to check it is something I don't know. There's a post on rebuilding the bevel gear and there's a company in Colorado which rebuilds Volvo driveshafts (there has to be more than one of them in the USA). How many miles on your V70XC? Kira

That was my fear - and am wondering if anyone has had any success rebuilding their own? I just hit 170k.

I have my 98 in the front drive club too, my problem is the bevel gear. I have a spare to put in... need time. Here is one non-dealer option
http://www.coloradodriveshaft.com/volvo.htm