XC60 D5 AWD Auto Angle Drive Gearbox issue

[SteveCurwen]

Hi Forum!!
As a newbie to the VOC I thought I'd like to share an issue with my XC60 (a 62 plate) D5 AWD Auto SE Lux Nav.
This was the wierdest problem I've come across and one that took Volvo nearly 17 weeks to fix! The car went in to Volvo at Gloucester on 29th September 2015. I got it back a week and a half ago 22nd Jan 2016!. What an epic tale!!

The issues first appeared last August when towing my caravan down to Cornwall. When stationary in traffic around Bodmin, (3hrs into an otherwise good journey) the missus and I got a horrible smell of gas (proper methane type smell). The usual comment from dealers and friends ranged from "It's probly your aircon" to "It's the DPF on it's regenerate mode - they do smell a bit".

Well it was none of these.

Johnsons Volvo at Gloucester have a good Master Tech (Colin). He and the team replaced injectors (apparently some have been known to leak a bit around 4th & 5th cylinder). They tried the CAT, manifolds, fluids including Aircon - you name it. No joy. Johnsons had to admit defeat.

The car was transported to Volvo UK at Daventry. They found the problem after a few weeks. The angle drive gearbox (that turns the drive from the front, 90 degrees and drives the propshaft) had 'cooked-up'. The gearbox oil is filthy stuff and the smelly burnt oil was venting out of the breather on top, trickling upwards by convection and finding its way into the cabin air system. The issue was consistent with this and would only appear when really slow or stopped and with fan on low. Recirculate would eliminate it, travelling forward at moderate speed would eliminate it. Such a wierd issue.

Volvo replaced the gearbox under warranty (which expired Nov 2015). I have some concerns though and would like to share my thoughts with the forum.

There could be a weakness with the AWD system stemming from a newer '3rd generation' Active On-demand Clutch (AOC) unit at the back of the propshaft feeding the rear wheels. Apparently the oil system sludges up and holds the car in 'permanent AWD' this in turn cooks-up the angle drive gearbox. This was the description given to me from Volvo.

I am concerned that the car only has 25,000 miles and is only 3 years old but this happened. Apparently the 3rd Gen AOC units are much smaller than previous generations and are prone to sludging up.

My advice is to get it checked on a major service. Apparently the newer units do not require that the prop-shaft is removed to get at the oil pump and scavenge filter.

A big tell-tale for me (beyond the horrible gas smell) was the consumption was up. I was down to 30-31 MPG (not towing) which was much worse than the 35-36 MPG I was seeing on general motoring (using adaptive cruise). My D5 is the 215HP SE Lux Nav Auto (6 speed) so 35-36 seemed OK. 31 MPG was not good. My current MPG is around 34 so I'm keeping an eye on it.

Please be aware that this drop in MPG can be an indicator that AWD is engaged permanently. In turn your AOC unit could be misbehaving.... in turn your angle drive could go for a burton!

I may have just got a 'Friday-afternoon' angle gearbox, who knows?

I hope to post updates with good news after a few months of monitoring..

[Fat Magpie]

Active on demand clutch, thats the Haldex clutch.

A stuck valve or contaminated oil maybe.

[Warkman]

Exactly the same setup as on Freelander/Evoque/Discovery Sport.

I have never heard of this issue and I worked with the diff guys for four years.

All the extensive testing if the torque on demand never showed this as an issue. Only issue was if you got water (small volume) into the duffs caused issues hence the reason why the vent pipe is so high