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braggxc70
01-29-2018, 07:48 PM
On my 2011 xc70 T6 with 185k km, I suspect that the front CV joint on the prop shaft is going bad. I found a grey grease sprayed around this joint, and am hearing an increasing humming sound from the driveline. Does anyone have experience replacing this joint on the P3 AWD model? I have found plenty of threads on the P2 forum, but not on the P3 forum. Any tips for DIY? Do I have to remove the prop shaft from the vehicle to replace this joint?

braggxc70
04-07-2018, 09:12 AM
I'm glad to see that no one seems to have experience with this yet. Hoping that at someone may benefit from my experience, here's an update:
1. I removed the prop shaft to inspect the front CV joint. It indeed leaked grease because of a rubber gasket that was not installed correctly (from the factory). After a thorough de-grease and inspection, I found the joint to be in good mechanical condition and re-greased and re-installed it. While I had the opportunity, I also inspected and re-greased the rear CV joint.
2. Unfortunately, after re-installing the prop shaft, the driveline noise still persisted. At this point, I had the dealer troubleshoot the source of the noise by putting the car on a lift and "driving" it. The unfortunate diagnosis is that the rear differential pinion bearing is failing. The shop foreman was great at letting me see and hear the issue so I have no doubts as to the correctness of the diagnosis.
3. Apparently, the differentials used on the 2008-2014 XC70's are prone to this failure (do an internet search and you will find more on this). Volvo only sells a replacement differential at $4000+, excluding removal and installation. A very pricey repair! The same differential has been used on Land Rovers, and Land Rover does sell the parts for a replacing the pinion bearing only. My dealer had these parts in stock, and will rebuild the differential next week. Total cost for this repair is ~$1900. Still not cheap, but at least better than having to buy a complete differential.

I hope this helps to alert people to this potential failure. It's important to troubleshoot and repair early enough where the bearing does not completely destroy itself and the metal parts do more damage to the rest of the differential.

Lastly, it's pretty disappointing to see this type of failure on our Volvos that have a reputation of reliability...

Our third Volvo
06-08-2018, 08:22 PM
HI Bragg

I may have the same issue with a 2010 with 145K miles. Have you done the repair yet...? Our only hum lightly during deceleration....

Mike in NJ

braggxc70
07-02-2018, 07:00 AM
Hi Mike in NJ,

Yes, I've done the repair on my vehicle. Unfortunately, I have to report that the driveline 'hum' was a separate issue from the from CV joint losing it's grease. After removing the prop shaft, I found that the CV joint had a gasket that was not aligned properly, allowing grease to escape over time. The joint still had sufficient grease to avoid excessive wear, so I put everything back together with a new load of grease, and a properly installed gasket. This did not fix the driveline hum, though. As you pointed out, the humming occurred mostly on deceleration, and in my case around 80kph constant speed.

To avoid further 'trial and error', I had my local Volvo dealer diagnose the noise, which turned out to be from the rear differential. It appears that our vehicles have a differential that is prone to failure of the pinion bearing. The only repair that Volvo offers for this failure is a replacement of the differential, which is a ~$5k cost! 'Luckily' this differential has also been used on Land Rovers, which have seen the same type of failures, but Land Rover offers a repair kit instead of forcing its customers to buy a complete replacement differential. My Volvo dealer was aware of this situation, and had the tools and Land Rover parts to fix my differential. It still set me back around $2k Canadian.....

I hope this doesn't scare you, but it's probably good to get your noise diagnosed, and if it is the rear differential it's better to get it repaired before a catastrophic failure of the pinion bearing happens. If that happens, you'd still end up replacing the differential.

I hope this is not your issue, and you find a cheaper solution!

Our third Volvo
08-03-2018, 12:55 PM
thanks for any guidance.

Mike

braggxc70
08-03-2018, 08:26 PM
Mike,

I had tried to respond to your post, but somehow this reply was not posted. I'll try again:
Firstly, the front CV joint was losing grease due to a gasket that was not properly installed from the factory. After careful examination, I decided that the joint itself looked fine, regreased it and installed new gaskets from a replacement joint I had ordered on line. When I put the prop shaft back, unfortunately the driveline hum was still there.

At this point, I asked my Volvo dealer to diagnose the "hum". They quickly found the issue, which is the pinion bearing in the rear differential. Apparently, this is a know issue with the type of differential that was installed between 2010 and 2014 (from memory). This same differential was used on Land Rovers, and they experienced the same type of failure of the pinion bearing. The bad news is that this is a major repair, requiring the rear subframe to be dropped to remove the differential. Volvo is only able to supply a replacement differential, which I believe is around $5k (Canadian). However, my dealer said that they had invested in some tools and sourced the pinion bearing parts from Land Rover and so they could do the repair for around $2k. Still expensive, and annoying that a know defect like this is not covered under warranty (mine is expired).

I hope my experience doesn't scare you too much..... The symptoms of my 'hum' were: initially mostly on deceleration, and most pronounced around 80km/hr. Gradually, the hum was getting more pronounced and was also present when maintaining speeds between 70 and 90km/hr. If your symptoms are similar, I'd get it checked out soon to avoid excessive damage that would necessitate replacement of the differential.

Good luck with your repair!


Henk

braggxc70
08-03-2018, 09:04 PM
Hi Mike,

My CV joint issue turned out to be a separate issue from the "driveline hum". The CV joint had a poorly installed gasket from the factory, which allowed grease to spray out of the joint over time. The joint was still in good condition, so I cleaned, regreased and re-sealed it. Did however did not fix the driveline hum.
My hum occurred initially on deceleration, and developed to being clearly noticeable at speeds mostly between 60km/hr and 90 km/hr. I had my dealer diagnose the hum, and by putting on the lift and running the driveline they quickly found the rear differential the source of the noise. Apparently this is a know issue for the type of differential that was used between 2010 and 2014 (from memory, but if you google you'll find more). Volvo only offers a complete replacement differential at a cost of ~$5k Canadian. Fortunately, my dealer knew that Land Rover also use this type of differential, and they offer a repair kit for the pinion bearing. My repair by using this repair kit was still $2k, and was not covered by warranty (since mine has expired). I found it disappointing that Volvo does not offer support for a known issue like this!

I hope this helps, and hope that your issue is easier and cheaper to deal with!

Henk