XC70: Gearbox 4wd not working?

[stimperley]

Our 08 XC70 has a frequently occurring ABS fault usually triggered by tight left hand corners so I am investigating wheel and diff bearings - there is also some whine which doesn't seem to be wheel bearings because its not affected by cornering. However, the immediate concern with winter here is that the 4wd isn't working. I'm hoping its just due to the ABS fault but what else could it be? The car is an early Phase 3 and I read somewhere that some early ones had the same system as the Phase 2. How can I tell? I know they had a reputation for breaking - whats their issue?

Thanks!

[Puffster]

I thought that they have an electronically controlled AWD system but most of the time it is FWD, so hard to work out if its not working except in very slippery conditions. Get it on a wet field and boot it (permission of landowner required I'm sure)

[Tannaton]

Originally Posted by stimperley

Our 08 XC70 has a frequently occurring ABS fault usually triggered by tight left hand corners so I am investigating wheel and diff bearings - there is also some whine which doesn't seem to be wheel bearings because its not affected by cornering. However, the immediate concern with winter here is that the 4wd isn't working. I'm hoping its just due to the ABS fault but what else could it be? The car is an early Phase 3 and I read somewhere that some early ones had the same system as the Phase 2. How can I tell? I know they had a reputation for breaking - whats their issue?

Thanks!

Firstly get it in to a garage and get the codes read with proper Volvo gear - it will likely tell you exactly what the problem is and save you a world of pain.

If it's reporting a "tone ring" failure - it's 99% likely a wheel bearing - even if you have no noise or play.

You can stop it from causing the car to hesitate by disabling DSTC in the menu when you start it up.

This should not affect the AWD. With AWD the problem cars where pre 2005 MY with the 163 BHP engine - later cars including yours are very reliable.

As said find a wet grassy field and boot it hard whilst turning and with DSTC off - if AWD is working the car will put the tail out.

[stimperley]

Appreciate the replies - come them coming!

It does give a tone ring problem on the rear sensors so hope it is a bearing - interesting you say no noise or movement. How do I detect it? Front wheels were spinning on a slippy slope recently and AWD didn't kick in but it was only for a short time. I'll keep trying that.

[stimperley]

Originally Posted by Tannaton

Firstly get it in to a garage and get the codes read with proper Volvo gear - it will likely tell you exactly what the problem is and save you a world of pain.

If it's reporting a "tone ring" failure - it's 99% likely a wheel bearing - even if you have no noise or play.

You can stop it from causing the car to hesitate by disabling DSTC in the menu when you start it up.

This should not affect the AWD. With AWD the problem cars where pre 2005 MY with the 163 BHP engine - later cars including yours are very reliable.

As said find a wet grassy field and boot it hard whilst turning and with DSTC off - if AWD is working the car will put the tail out.

Just realised that you gave me a load of advice on this a year ago. I've lived with it ever since! (Got it through the MoT by only turning right!!) Just one thing - if LH corners set it off is it most likely the right rear bearing? Both fronts changed previously. Maybe both given both sides give error codes ...

[apersson850]

XC70 2008-2012 have Haldex (now Borg Warner) generation IV. 2013-2016 have generation V.
None of them are applied during normal driving. But starting uphill in wet grass, let alone snow, you'll be able to tell the difference immediately. You don't need any heavy right foot for that.

[Tannaton]

Originally Posted by apersson850

XC70 2008-2012 have Haldex (now Borg Warner) generation IV. 2013-2016 have generation V.
None of them are applied during normal driving. But starting uphill in wet grass, let alone snow, you'll be able to tell the difference immediately. You don't need any heavy right foot for that.

The very early P3 XC/V70's had Gen 3 haldex until MY2009 cars.

[Tannaton]

Originally Posted by stimperley

Just realised that you gave me a load of advice on this a year ago. I've lived with it ever since! (Got it through the MoT by only turning right!!) Just one thing - if LH corners set it off is it most likely the right rear bearing? Both fronts changed previously. Maybe both given both sides give error codes ...

You need to get the codes read.... it's usually the rear wheels that cause this, in which case it will likely be the LH bearing as the cornering forces being applied will cause the wheel to "tip in" at the top and hence move the tone ring on the CV joint further away from the sensor.

Don't assume the fronts are okay as they have been replaced unless you used Volvo original bearings or a quality part like SKF.

[stimperley]

Originally Posted by Tannaton

You need to get the codes read.... it's usually the rear wheels that cause this, in which case it will likely be the LH bearing as the cornering forces being applied will cause the wheel to "tip in" at the top and hence move the tone ring on the CV joint further away from the sensor.

Don't assume the fronts are okay as they have been replaced unless you used Volvo original bearings or a quality part like SKF.

I was told both rear sensors were showing errors but I'll start with the LH bearing, thanks for the info - just ordered an SKF from autodoc on your recommendation

[apersson850]

Originally Posted by Tannaton

The very early P3 XC/V70's had Gen 3 haldex until MY2009 cars.

Ah, sorry if I was off by a year or so.