XC60 Rear Drive Unit
 

We have a 2010 XC60 D5 AWD Manual, roughly 70k miles. There is a drone from the rear that starts at 50mph. At first I thought it was a failing wheel bearing but it doesn't get louder with increased speed but does get change slightly with more power.

The local dealer had a look and diagnosed a problem with the rear drive. They have quoted £5k to change the primary and secondary "final drive units". After picking myself off the showroom floor, I thought I'd do some research.

What has really surprised me is that there is barely a mention on the internet of an XC60 AWD rear drive failing. You can usually find discussion about any fault on any car somewhere so clearly this one is not a common fault. There's just one other thread on this forum => http://www.volvoforums.org.uk/showthread.php?t=221154

Does anyone know anything about how these units fail? Is it reasonable to change both units or is the dealer just doing a blind replacement instead of identifying the cause of the problem?

ps We've not had any warning messages about AWD.

Firstly there are TWO separate units with bearings and their own oil supplies, the rear final drive which most rear wheel drive cars have , then there is the Haldex clutch unit on the front of the final drive which also has a bearing ... Yes they are being very wrong in not diagnosing which is causing the noise , It should be straightforward running it on the lift and listening underneath to the unit .

The bearing in the Haldex is fairly straightforward to change and the final drive can be repaired too . But a dealer will not go that far . parts will be well under £100 ...

If you get the noise suddenly at around 50 mph and not before it's because that's when the torque converter locks in top gear - do you see the rev counter needle drop a bit as the noise arises and does the noise disappear if you come off throttle? If so could be propshaft joints, bearing etc. Suggest do a search on XC90 forum also - -a few people have had similar issues.

Yes, that's my thread.

I had pretty much similar experience as you, my (then) 6 year old XC60 has just 32K miles on the clock. Sounded similar to a wheel bearing. The dealership pretty much laughed at me on the phone when I told them a local engineer had suggested it wasn't a wheel bearing but a rear diff issue "never heard of that with an XC60". But a failure it was.

Given mine was £2700, I can't see how it would now be £5K, so it sounds like they are replacing more than is necessary. It might be worth asking your dealer for an extraordinary contribution. I might have been "lucky" in that mine was really pretty low mileage.

The dealer quote is:
Primary final drive unit - £2,900
Secondary final drive unit - £2,300

It's booked into a specialist indie to see if they can be more sensible about what needs to be done.

what is their explanation for changing both units ? It is like changing the engine and gearbox because there is a vibration somewhere . I explained above how to fix it for a reasonable price ... if you cant do it yourself a gearbox/axle specialist will be able to .

The indie has come back to me after 2 road tests and time on the lift. The noise can't be detected on the lift because there's no load through the transmission. They've checked the wheel bearings as well as the AWD transmission.

He has seen failed AWD before but says it needs to be a louder noise to diagnose where it is coming from when the car is on the lift. He also said that he sends problematic AWD boxes to a specialist Haldex chap to get the relevant bearing fixed.

So I've found the right person, but I just need to get some more miles on the car!

I'll phone the dealer to give them a piece of my mind.

If the oil is original, get it changed. That may be all that's needed. Also make sure that the tread depth is roughly equal on all four wheels. Some tyres drone like crazy at certain speeds as they wear down, especially for the last third of tread, so make sure its none of those.

I haven't read the other thread, so forgive me if that has already been covered.

Admittedly an old thread, but it's worth posting an update :

@Tannaton got it right about the noise kicking in at 50mph and the sound dropping with reduced power.

I lived rhythm it for about 6 months expecting it to get worse but it then faded away to nothing. Very odd.

Now at 99k and 9 years old this month but refuses to show any signs of age.