Propshaft, VC, Bevel Gear, Clunks, whirs - Diagnosis and solutions

[8pack]

Maybe this is worth a Sticky. Not sure who decides.

This is for a 2000 XC70. Should be the same for all years but i can't be sure, particularly on the part #s.

After research and trial and error, here is a primer on how to figure out what the source of your problem is when you have drivetrain issues. I have taken the driveshaft in and out 3 times, to figure this out and used some of the information from the long post in the link below to figure out the issue, diagnose and solve it.

Link Reference:

http://www.v70xc.com/forums/showthread.php?t=17186

Thunk:

A thunk is defined as a loud "thunk" or "bang" that you can physically feel come up through the bottom of the car. Like it is being hit with a hammer. Typical symptom is when moving from park to Drive or reverse to drive or drive to reverse. When you are in motion all will be as normal and there will be no noises except when you come to a stop and start again. Upon starting again you are likely to get the thunk.

Probable Cause and Diagnosis:

It is highly likely it is the mounting bushing on the front of the viscous coupler. Here is what happens. The rubber bushing itself will look good. There will be no evidence of side to side movement. What you won't realize or be able to spot initially is that the bushing has separated from the steel carrier. When you put the car in gear and the drive train engages, as it torks the VC, the VC rides up over the rubber bushing and hits the bottom of the car making a "bang" or "thunk". This won't come on particularly slowly, from the 1st hint of a thunk, to a full blown bang will only take a few drives. To verify this is the case there are a few things to do and look for.

1st put a jack under the viscous coupler to hold it up. Ideally you should remove the bolts holding the propshaft to the VC (see below for instructions on propshaft removal, in this case just the rear should be uncouples). Remove the bolt holding the front of the VC to the underside of the car. Slowly lower the jack letting the VC and Rear differential come down until they rest on the large aluminum bracket that holds all the rear suspension parts together. Once you get under there this will all be self evident.

Now check for 2 things. 1st see if the busing is securely in place. Mine popped out when i pushed on it. Push and tug HARD. It should not slip or otherwise move in the fitting. If it does, bingo you know your problem without further exploration. The other telltale sign will be to look at the underside of the car, just above the VC. If the VC is riding up in the busing you will see a mark in the aluminum heat shield or underbody where the VC is banging into the floor. On mine it was a small indentation and took some finding. To confirm it was a mark as a result of the bad bushing, I just pushed the VC up into the bottom if the car and verified that the VC lined up with the spot where I thought it was hitting on the underside.

Solution:

Remove Bushing and replace! $32 at Volvo. Part # 9143894. In the thread referenced above, YL staffer says you don't have to remove the VC. I can see how that is possible if you are prepared to cut the old steel retainer away from VC housing by slicing it in 3 places and prying out the old pieces being careful not to cut into the aluminum. To refit the bushing you would have to use the bolt and the washer to press it into the housing while remounting it to the under carriage. That may all be quite possible, but you risk galling the mounting area for the bushing or damaging it removing the old steel carrier. I called my Indie and for less than $200, he said he would pull the VC, press out the old bushing carrier, press the new one in and remount the VC and the propshaft. For me good insurance.

Total Repair Cost $35 - $250 Max

Banging, clanking, rattling:

The definition of these is something that results in any of those noises when moving the car into or out of gear and continues in some form including vibration etc. while moving. The noise will likely exists on starts with solid acceleration, but may not be noticeable on soft or slow starts or very slow speed driving. Greater speed is likely to make more noise which may in fact come and go at different speeds. In severe cases there will be consisting clanking or banging that feels like it is coming through the drivetrain or car, but NOT like a thunk that is physically hitting the body. It may feel as if someone is under the car hitting the transmission case or rear end and as I said above like it is being transferred through those parts, not directly hitting the body.

Diagnosis:

This is very likely a bad propshaft. The noise if from one of the couplers that has broken free or loosened up in its fitting. Also possibly the center u-joint has gone bad.

Solution:

Remove Propshaft, replace. You can have it rebuilt for around $450 or purchase a "new one" for $635. The "new" version has a modified U-joint with a grease fitting which is nice. That's what I bought.

Removing and replacing the driveshaft is a very easy do it yourself job. No experience required.

Should not be more than $100-$150 for labor and $450 - $650 for the parts.

Link Colorado Driveshaft - Rebuild

http://www.coloradodriveshaft.com/

Link Axles Unlimited "New"

http://www.axlesunlimitedinc.com/

Whirring, Grinding.

These noises are usually associated with the VC or Bevel gear. You may feel some thinking etc, but it will be associated with a definite drivetrain noise.

Diagnosis:

Noise under your feet=bevel gear. Noise from behind VC.

Solution:

Replace VC or Bevel Gear. Viscous coupler, small job $350 for the part at Eerie Volvo and $200 to take it out and put a new one in or do it yourself for nothing.

If Bevel gear, job, no cheap way out. No idea how to do that job.

Remove Propshaft Instructions:

Ideally put the car up on 4 jack stands with all four wheels off the ground. Make sure it is solid and secure. Roll underneath. you will see the front of the propshaft attached to the bevel gear just in front of the catalytic converter. The rear is attached to the VC. Both are attached with 6 allen bolts, 6mm drive. To remove the bolts it is best to have a helper. Put the car in neutral. and the e-brake on. You will find on the rear that having the bolt at the 6 o'clock position will make it easy to remove without any clearance problems with the ratchet. In the front it will be in the 9 o'clock position. Other positions and it is hard to get the ratchet to engage properly. Remove one bolt, have your helper release the e-brake and then rotate the wheel until the next bolt is in the right position, re-engage the e-brake and remove the next bolt. Rinse, repeat.

Once all the bolts are removed, move to the center of the car where the u-joint on the propshaft is. There is a large bracket that is attached to exhaust hangers and goes over the propshaft. It is held on with 4 bolts. Remove the 4 bolts. The center carrier bearing on the propshaft is bolted to this bracket. Use a 10mm box wrench (spanner for you foreigners) and remove the 2 bolts. Now you need to break the propshaft free at the front and back. some good hard pulling and wiggling should break it free although you may need to wack it good whee it mounts to the VC in the rear. Don't bother trying to break it free until you have removed this bracket and the center carrier bearing from the bracket. Once the rear is free, a good pull and wiggle will break the front free. I thought mine would not come free in the back, but with persistence it eventually came loose.

To reinstall, reverse the process. Very easy if you can remove bolts and install them.

Thanks to YLStaffer, JRL and others who provided info to figure this out.

Let me know if you have any questions or edits...

[ylstaffer]

Holy cow 8pack this is awesome!

The one thing that I did forget to mention at the end of my scenario is that the metallic 'rubbing' noise I had been hearing was simply noise from the drive line transferring through the bad bushing and vibrating the under body of the car. With the new bushing the noise has disappeared.

Case officially closed. At least for now. And we've had snow here and the XC has performed beautifully, climbing slick hills without a slip, passing by others who weren't as fortunate.

[MikeInOregon]

ylstaffer, which bushing did you replace to get rid of the metalic rubbing noise?

[ylstaffer]

It is the one where the mounting arm from the VC housing mounts to the under body of the car.

[IRMB]

It is the one where the mounting arm from the VC housing mounts to the under body of the car.

Bump. So I can find it later.

This is great thread. It would be better with pics, though! If and when I do mine, I will add.

[vova]

http://www.volvoxc.com/forums/showthread.php?t=18819

Here is some feedback about angle gear rebuilt and link for angle gear parts and prices which will be helpful for someone who is crazy to do it himself as i was. Thanks for a great post! It is really helpful. Sure it deserve a sticky.

P.S. Just totally unrelated. personally i think that volvo awd is a total piece of C**P!!!! Why they did not put the engine in line with the car so there will be no need for stupid angle gear and long prop shaft which fails after 100K?????? I have an 02 outback sedan 3.0 -no problem with awd at all(160K) just change fluids...no vibration..just clean and smooth reliable staff..Audi since early 80`s used the same configuration of awd components and no problems there(used to have an 87 Audi 100 Quattro with 200K- no vibration of propshaft or etc..)
I have 98 and 01 XC and both need propshafts..my friend has an 00 same story-"just feel the vibration!!!"
Yes i am angry about the poor design..about high maintenance cost of parts
that does not suppose to wear so fast..(don` even want to talk about my fathers 97 accord station wagon with 250K because i would be ashamed about the reliability of volvo)
I LOVE Volvo`s- comfort, safety,engine,design, but awd...

[JRL]

Because the car will not "crash" well and that is Volvo's no# 1 priority
The engine would wind up in your lap and have you ever seen many FWD cars with engines that face North/South? Not many on a "smaller" car

[vova]

Sorry to say that, but in a recent years volvo does not performed as well on a crash tests as it used to.http://www.iihs.org/ratings/tsp_archive.html looks like situation changed for better during 2011-2012 years but in terms of reliability we will not be able to say anything till those cars hit the 5 year milestone. Just agree that not too many people can afford to trade in a car with 45-55K on it and 5 years since new..( if they can-I wish them prosperity for years to come) For many used car buyers Volvo still employs the trust that it earn during 80`s-90`s but it losing it`s positions now. Just take a look on Subaru crash test ratings with their awd/engine configuration...
Same sad story with Audi, BMW,MB..High maintenance, poor reliability, and extra high cost when new. A few of my friends have Acuras and Lexus's and need to mention Buicks`s( just hard to say what Buick was able to do in just a couple years..respect) and those cars require much less maintenance than Volvo or other luxury brands..
Maybe I am just stupid idiot "made in USSR" who does not see further than his nose, and do not know anything about cars, who knows..
I just express my view of the situation and try to be objective. I love my XC`s and enjoy them for what they have to offer(once again I was amazed today by cargo capacity of my 98 ) unfortunately they have a lot of problems that occur way too often with way too many cars. I realize that all XC`s are based on FWD versions and that for the factory it easy to stick a angle gear in with an extra long propshaft..
I just surprised that cars in $35000-$45000 range are so unreliable. But hey, who am I to judge cars? My goal is to be able to make enough money too be able not to think about all those little issues..wish you friends the SAME!!! Let keep them rolling!

[StoningtonXC70]

Great post. When I removed my driveshaft due to a bad center bearing last summer, I scribed match marks on the angle gear and VC flanges as well as on the driveshaft front and rear flanges, also noted the locations of the the individual hex bolts relative to the match marks.

When I finally get around to putting in a rebuilt or new driveshaft, is it absolutely necessary to have the scribe marks on the angle gear and VC in alignment? Is there a particular position I have to install the new shaft in relative to the marks? What if I can't find the scribe marks on the AG and VC flanges? I am concerned they might not be visible any more.

Car has been fine so far in snow without the AWD, but want to get the shaft back in at some point.

[vova]

Great post. When I removed my driveshaft due to a bad center bearing last summer, I scribed match marks on the angle gear and VC flanges as well as on the driveshaft front and rear flanges, also noted the locations of the the individual hex bolts relative to the match marks.

When I finally get around to putting in a rebuilt or new driveshaft, is it absolutely necessary to have the scribe marks on the angle gear and VC in alignment? Is there a particular position I have to install the new shaft in relative to the marks? What if I can't find the scribe marks on the AG and VC flanges? I am concerned they might not be visible any more.

Car has been fine so far in snow without the AWD, but want to get the shaft back in at some point.

I think that it will not make a difference. the new shaft will be properly balanced and marks on BG and VC will not be needed. The only difference(as it was mentioned in some earlier posts will be to put longer bolts oposite to each other for the optimal balance.)
But it is my guess. I am interesting in the same question now since i am planning to remove the propshaft from my 01.