XC70 loss of drive

**paultyler1** · Tuesday 6th January 2009, 19:55

My 2004 XC70 seems to have lost drive to the rear wheels. I've been stuck with the rear wheels on tarmac but the front ones deep in mud and it wouldn't pull itself out. There are no ominous mechanical noises and no warning lights showing. Anyone got any ideas as to what the problem is?

**850twr** · Saturday 10th January 2009, 00:08

it could well be that the pins have come out of your "active on demand" coupling, which is on your propshaft, and basically determines when power should be transfered to the rear. These are a common fault, and there was a recall carried out by volvo from what i can remember, and we changed quite a few in the time that i worked for volvo.

i'm afraid i cant remember the price, but the unit will need to be changed (assuming this is the problem), as the pins can't simply be replaced.

the other thing it could be is the transfer box, and they are not cheap, but i would expect there to be atleast some unwanted mechanical noise.

hope that helps. Nick.

**paultyler1** · Tuesday 13th January 2009, 21:49

Hi
Thanks for this - is it possible to see the pins from underneath or are they hidden? Also, how can I find out if there was a recall on my vehicle and whether or not the work was carried out?
Thanks for your help.

**850twr** · Thursday 15th January 2009, 23:05

you would need to crawl right under to the center of the car (atleast you have the ground clearence on a xc) follow up the propshaft untill the diameter almost doubles (looks like a big metal donut) and the plastic pins are all the way round on the side of it. It was either a recall or atleast a notification put out to dealers for ALL XC70's of that era, just give your dealer a ring and get them to check through the history for you.

**paultyler1** · Friday 16th January 2009, 14:49

Thanks for this - have crawled underneath and can see a doughnut shaped piece at the back (just before the diff) - is this the part you mean 'cos I can't see any trace of plastic pins.

**850twr** · Monday 19th January 2009, 15:07

Originally Posted by paultyler1

Thanks for this - have crawled underneath and can see a doughnut shaped piece at the back (just before the diff) - is this the part you mean 'cos I can't see any trace of plastic pins.

no from what i remember its more central of the propshaft, you will definitely have one.

**paultyler1** · Wednesday 4th March 2009, 13:03

Now had car repaired and was preparing myself for a mega bill (up to £3k according to the dealer). But, surprise, it was a £90 pressure sensor that was at fault. Total bill (including new pads, discs and a major service) was £1200.