xc90 no rear wheel drive

[tallboy10]

I wonder how prevalent the loss of 4WD is on XC90's? I purchased my 54 reg xc90 2.5 auto in March of this year (not from a main dealer unfortunately)... I had noticed some slight front wheel spin for a few months but today's minor fall of snow left my mighty 4WD XC90 struggling up a small gradient out of my drive, front wheels spinning very theatrically. No warning lights, no messages from the computer... Not sure if this if this is a prevalent fault but it seems to have happened to a number of others... I have noted that Volvo have been stepping up to pay to have this fault rectified out of warranty, I can only take the car into the local dealer and see what they have to say. will keep you posted

[4wheeldriver]

HAd some quite deep snow round here few weeks ago and my xc90 was quite sure footed. it went up the hill to a friends house when her "(un)intelligent grip" Audi tt quattro wouldnt go up to the house! The Volvo sailed up in "W" mode, dropped her and the shopping and sauntered back down again!! Even with the DTSC switched off I still couldnt provoke it to do anything daft!! Would say the one you'd to tow this morning has a rather large problem somewhere

[tallboy10]

well i watched the race on top gear between clarkson and may in a 90 and a q& and i believe the 90 won... on snow, deep snow, with clarkson using a uzi as he did a nordic drive round vs may with a rifle.... i know they go well - its just irritating that this fault appears to happen with no visible warning signs to the driver.. I tried it with DTSC on and off and its marginally better... oh for a manual diff lock and HiLo range (i used to drive military landrovers) and there was little to go wrong with the drive train!

[Clan]

firstly see if the front wheels turn when you rotate the propshaft by hand , if yes then the front end is ok ...
If no , then suspect the splined sleeve connecting the front crown wheel to the angle gear ..

If the front end is ok then suspect the oil pressure sensor in the Haldex and easy job to change , your dealer should be aware of the details ...

Regarding transfering power from the left to right wheel on the same axle , the brake is applied to the wheel with least tracton transfering the power across to the wheel with the grip ..
The sytem normaly works fine , if the two left wheels are parked on slippery grass and the two right wheels are on tarmac , the car will pull away well .

But if you are stuck on a very slippery surface no 4 wheel drive vehicle will get traction where non is available ...

[GSMGuy]

Firstly, the XC90 is not full time 4wd, as say a landie or range rover, it's front wheel drive UNTIL it detects a loss of grip, then it closes a clutch/solenoid and power is transferred to the rear wheels via the rear diff.. Obv if it's seldom used, ie the car is driven mostly on the normal road, I presume things can seize up through lack of use..... The way I have tested mine in the past is ; fron wheels on the muddy verge, rears on the road, and me spectating whilst someone else tries to take off sharpish..... Visibly saw the fronts spin slightly, and then stop as the rears engaged and took up drive... Quite easy to see...

Mike

[RoyMacDonald]

Originally Posted by GSMGuy

Firstly, the XC90 is not full time 4wd, as say a landie or range rover, it's front wheel drive UNTIL it detects a loss of grip, then it closes a clutch/solenoid and power is transferred to the rear wheels via the rear diff.. Obv if it's seldom used, ie the car is driven mostly on the normal road, I presume things can seize up through lack of use..... The way I have tested mine in the past is ; fron wheels on the muddy verge, rears on the road, and me spectating whilst someone else tries to take off sharpish..... Visibly saw the fronts spin slightly, and then stop as the rears engaged and took up drive... Quite easy to see...

Mike

It always has at least 10% to the back Mike. It also switches the drive front to back as you go round a bend to give neutral handelling. According to Volvo anyway.

I'd look to the tyres as well. I'd fit an all year round tyre like the Nkian WR's or Vredstien Wintrack 4 Extreme's.

All the best.

Roy

[GSMGuy]

Have to disagree Roy...

Taken from Volvo's webpage just now:



Drive is only engaged to rear wheels when slippage of fronts or loss of traction is detected - in general use the XC is FWD only...

Mike

[RoyMacDonald]

Originally Posted by GSMGuy

Have to disagree Roy...

Taken from Volvo's webpage just now:



Drive is only engaged to rear wheels when slippage of fronts or loss of traction is detected - in general use the XC is FWD only...

Mike

That's animation is a bit simplistic Mike. Look at page 102 in your handbook. Also cut and pasted from one of Volvo's PDF on the subject which seems to be to big to upload but if you want to PM me your email address I'll send you, it only 5% to the rear in normal use though not 10%.......I NTELLIGENT FOUR
WHEEL DRIVE
THE VOLVO XC90 HAS BEEN CREATED FOR VERSATILE USE. IT HAS THE
PERFORMANCE THAT RESULTS IN GOOD DRIVING CHARACTERISTICS
UNDER EXTREMELY VARIED CONDITIONS. THE INTELLIGENT FOUR-WHEEL
DRIVE UTILISES THE ENGINE'S POWER OPTIMALLY. THE DRIVING
EXPERIENCE IS ENHANCED BY THE PASSENGER CAR CHASSIS AND THE
GRACEFUL BODY.
NORMAL DRIVING
During normal driving on a dry surface, nearly all tractive force goes to the
front wheels (> 95%).
ACCELERATION
During acceleration, the AWD system distributes engine power between
the front and rear wheels so that the greatest amount of power is
transferred to the ground and can be utilised to propel the car forward.
Thus, the AWD system contributes to the car's good acceleration capacity,
particularly on rough surfaces.
ELECTRICALLY CONTROLLED HYDRAULIC COUPLING
Engine power is distributed automatically between the front and rear pairs
of wheels with the help of an electronically regulated, hydraulic coupling.
This new type of hydraulic coupling reacts very quickly and can transfer full
torque before the wheels have even turned much. This quick reaction
reduces the risk of the front wheels digging down into e.g. loose sand.
INTELLIGENT AWD
The Volvo XC90 has been developed with permanent drive to all four
wheels. Tractive force is automatically distributed between the front and
rear wheels. This is regulated electronically, and is affected by the road
surface and driving style.
QUICK AND SMOOTH REACTIONS - ALL-WHEEL DRIVE
Tractive force is automatically distributed.
between the front and rear wheels.
This is regulated electronically,
and is affected by the road
surface and driving style.
I F THE FRONT WHEELS SPIN
If the road surface is such that the front wheels begin to spin, more
tractive force is distributed proportionately to the rear wheels. This
redistribution of force takes place very quickly, without the driver being
aware of it.
TRACS
Distribution of power between wheels
on the same axle is controlled by the
anti-spin system TRACS. If one of the
wheels begins to spin, TRACS ensures
that power is transferred to the other
wheel on the same axle. This
contributes to the best possible
starting and driving characteristics,
particularly on slippery surfaces.1 6
SAFETY
CRUMPLE ZONES
The front and rear crumple zones
dissipate and distribute incoming
collision forces so as to reduce
the physical strain on the
car's occupants.
PROTECTIVE SYSTEMS FOR OTHER
ROAD-USERS
The front structure and bonnet are
designed to help reduce the risk of
injury to unprotected road-users. For
occupants of other and smaller cars,
there is an additional lower
cross-member below the front
bumper that activates the
second car's own crumple zones
more quickly.
" CARS ARE DRIVEN BY PEOPLE. THE GUIDING PRINCIPLE
BEHIND EVERYTHING WE MAKE AT VOLVO, THEREFORE,
I S - AND MUST REMAIN - SAFETY;"
ASSAR GABRIELSSON AND GUSTAF LARSON,
THE FOUNDERS OF VOLVO .
DUAL-STAGE AIRBAG
Registers the collision force and
adjusts inflation accordingly - with
full pressure for high crash forces, or
with reduced pressure if the crash
force is lower. If the airbag is not
needed, only the safety belt
pre-tensioners will be deployed.
SAFETY CAGE

SIPS SIDE-IMPACT PROTECTION
The sturdy safety cage surrounds all

Distribute crash forces in a side
the car's occupants and is

impact across a large part of the
dimensioned to withstand extreme

car's body so as to help minimise the
physical stress. strain on the occupants. IC inflatable
curtains for all the occupants and the
front seat side airbags offer head and
chest protection.
ENERGY-ABSORBING INTERIOR
All the panels and door sides are
padded with energy-absorbing
materials to help reduce the risk of
injury to the car's occupants.
PERSONAL SECURITY
An electronic immobilises and door
locks that withstand most break-in
attempts help protect against theft.
Approach and Home Safe lighting
li
ght up your path to and from the car
at the touch of a button on the
remote control. A remotely controlled
alarm is fitted as standard.
IC INFLATABLE HEAD-
PROTECTION CURTAINS
Offer protection irrespective of
whether you are sitting in the front or
rear. Inflate in a side-impact or roll-
over accident to protect the heads of
all the occupants. The curtains remain
inflated long enough to contribute to
continued protection in complex
collision sequences and to help keep
the occupants within the car.
REARMOST SEATS
Head restraints, three-point safety
belts with pre-tensioners, IC
inflatable curtain, generous rear
crumple zone - two passengers ride
as safely here as in any other seat.
The seat's position above the rear
axle contributes to added side-
impact protection.
SAFETY BELTS WITH
PR E-TENSIONERS
All seats have head restraints and
three-point safety belts with
pre-tensioners. In a crash or roll-over
accident, the safety belt is pulled
tight to help provide maximum
protection. The front safety belts
then slacken slightly so that the
occupant is cushioned by the airbag
in a controlled way .
RSC ROLL-OVER PROTECTION
RSC (Roll Stability Control) helps
you keep control over your car. If
the car rolls over, the IC inflatable
curtains and safety belt
pre-tensioners are triggered by an
electronic sensor. The windscreen
frame, roof and door pillars all
feature extra reinforcement to
serve as a roll-over cage.
WHIPS WHIPLASH PROTECTION
Volvo's own system for reducing
the strain on the spine and neck if
the car is hit from behind at low
speed. Built into the front seats,
and activated by a sufficiently
severe impact.
LOAD SAFETY
Loads are secured most safely using
the eyelets in the luggage
compartment floor. In addition, all the
seats are designed to withstand
considerable pressure from
unsecured loads. A cargo net or
protective cargo grille helps improve
l oad safety still further (optional).
CHILD SAFETY
An integrated booster cushion in the
centre rear seat ensures that the
safety belt is correctly positioned on
the child (standard). For younger
children, there are Volvo's
rearward-facing child seats with the
ISOFIX attachment system for the
outer rear seats and the front
passenger seat if no airbag is
fitted (accessory).
\THE THRILL OF EXCITEMENT FOCUSES THE SENSES AND ENHANCES THE SENSATION OF BEING ALIVE. THE FEELING OF BEING SAFE ADDS TO BALANCE AND
HARMONY - ALLOWING YOU TO ENJOY THE EXPERIENCE TO THE FULL. SO THE NEW VOLVO XC90 IS ALSO THE MOST SAFETY-MINDED CAR IN ITS CLASS.
The Volvo XC90 raises safety to a new, higher
level. The high seating position and superb
visibility make it easier to look ahead and avoid
potentially threatening traffic situations. A low
centre of gravity, all-wheel drive and a
sophisticated chassis combine to help give you
full control in all situations. Active stability
systems boost the safety margins still further, for
i nstance if you are forced to take extreme
evasive action. And if an accident simply cannot
be avoided, you and your fellow occupants have
the benefit of added protection by the same
world-leading safety systems that save lives in
other Volvo cars - as well as by Volvo's unique
roll-over protection system. The car's angle and the roll-over risk are both registered
by an electronic sensor. At a predetermined risk level, the
RSC (Roll Stability Control) system is immediately
activated, helping you to maintain control.
If you nonetheless end up in a situation in which the car
rolls over, the inflatable curtain is deployed to help
protect the heads of all the occupants and keep all
within the car. At the same time, the safety belt
pre-tensioners are activated in all the seats, keeping
you firmly in the seat.
THE VOLVO XC90 EMBODIES CONSIDERATION FAR BEYOND THE NORM, NOT LEAST FOR THOSE OUTSIDE THE CAR ITSELF. IT IS THE FIRST CAR IN ITS CLASS
THAT MEETS THE DEMANDS FOR GENEROUS DIMENSIONS, WORLD-CLASS CRASH PROTECTION, ENVIRONMENTAL CONSIDERATION AND - NOT LEAST - A
CONSTRUCTION THAT IS NOT UNDULY AGGRESSIVE AGAINST OTHER ROAD-USERS IN A COLLISION.
FOR OCCUPANTS OF OTHER CARS
The Volvo XC90 is designed and built from the
very outset as a modern passenger car with a
monocoque body and the same type of crumple
zones as found in the rest of the Volvo range.
Despite the high ground clearance, the body
structure itself is still at the same height as the
bumpers of most other passenger cars. In a
frontal collision or side impact, the additional
lower cross-member below the front bumper
activates the other car's own crumple zones
more quickly. This saves vital milliseconds
- time that may also save lives.
FOR UNPROTECTED ROAD-USERS
The front structure and bonnet are designed to
help reduce the risk of injury to unprotected
road-users. The front is gently rounded and the
headlamps are integrated flush with the body.
The low position of the engine has made it
possible to give the bonnet additional
energy-absorbing properties. It serves as a
crumple zone if a pedestrian is hit, thus helping
to reduce the risk of serious injuries.
FOR THE ENVIRONMENT
The very latest engine technology and highly
efficient exhaust treatment ensure that the
Volvo XC90 meets the toughest of international
environmental standards. At the same time, fuel
consumption is kept down so as to minimise
emissions of carbon dioxide. In fact, the Volvo
XC90 actually has a positive environmental
effect: the radiator has a special coating,
PremAir which converts harmful ground-level
ozone into fresh oxygen as the car drives by.EMPOWERMENT
I F THE REASON FOR GETTING THERE IS QUITE SIMPLY BECAUSE IT IS THERE... OR BECAUSE YOU
WANT TO CHALLENGE YOUR OWN CAPACITY AND LEARN SOMETHING ABOUT YOURSELF... OR BECAUSE
YOU WANT TO HAVE A GOOD TIME IN THE COMPANY OF GOOD FRIENDS IN THE OPEN AIR. THE NEW
VOLVO XC90 IS ABOUT DOING THINGS YOUR OWN WAY - WHETHER YOU TAKE THE HIGHWAY, THE
TWISTING COUNTRY ROAD OR THE REMOTE FOREST TRACK KNOWN ONLY TO A FEW.
The AWD system and the generous
218 mm ground clearance contribute
to the car's excellent get-you-there
ability in all road conditions.
You can fully enjoy the response of an
agile chassis and a smooth six-cylinder
petrol or five-cylinder diesel
turbocharged engine of 272 bhp or
1 63 bhp. When needed, a powerful
anti-lock braking system featuring
all-round ventilated discs and EBA
(Emergency Brake Assistance) is at
your disposal.
Power is in your hands. In Automatic
mode, the Geartronic transmission
adapts its gearchanging pattern to
suit your driving style. And if you want
to drive more actively, just switch over
to Manual mode.
The Volvo XC90 is an exceptionally rewarding
all-road driving experience. The low centre of
gravity and the weight distribution contribute to its
stable road behaviour. Multi-link rear suspension
provides excellent ride comfort and well-balanced,
consistent road manners. Driving stability is further
aided by the electronically controlled AWD system.
Drive is automatically distributed between the
front and rear wheels within fractions of a
second, as current conditions demand. DSTC
(Dynamic Stability and Traction Control)
automatically detects and counteracts any
tendency to skid. And should you be forced to
take extreme evasive action whereby the car risks
rolling over, the RSC (Roll Stability Control)
system steps in and brakes the wheels until the
car regains its poise, helping you to stay
i n control.ENGINE AND TRANSMISSION
VOLVO XC90 T6 (272 BHP)
An in-line six-cylinder 2.9-litre petrol engine, remarkably smooth and
with overwhelming power. The engine pumps out its full torque
potential (380 Nm) from just 1800 revs a minute, and then continues
to pull like a turbine across the full rev range. Dual turbochargers and
variable inlet valve timing promote superb performance. Low internal
friction and variable exhaust valve timing help keep the lid on
fuel consumption and ensure that the engine meets strict
environmental standards.
MANUAL GEARBOX
I f you prefer a more involving driving style and do not normally need
to haul heavy loads in awkward situations, you will enjoy the smooth
and distinct all-synchromesh manual gearbox which is available on the
Volvo XC90 D5 from mid-2003.
GEARTRONIC TRANSMISSION
With Geartronic automatic transmission, you get two gearboxes in
one: firstly, an adaptive automatic transmission for relaxed driving, and
secondly a manual gearbox for when you want to drive more actively.
I n Automatic mode, the transmission registers your driving style and
adapts the gearchanging pattern accordingly. The auto transmission is
also perfect if you need to get the car to crawl slowly with a heavy
l oad under difficult conditions. A separate Winter mode makes it
easier to get under way when conditions are slippery. In Manual
mode, you change up by pushing the gear lever forwards, and down by
pulling the lever towards you. (A four-speed Geartronic transmission
i s standard in the Volvo XC90 T6. Five-speed Geartronic is available
i n the Volvo XC90 D5.)
ALUMINIUM ENGINE PROTECTION SHIELD'
Protects the engine, sump and transmission from bottoming when
driving on really rough terrain.
AUTOMATIC LEVELLING
For more stable roadholding, better comfort and unaffected ground
clearance when driving with heavy loads or using the car for towing.
The shock absorbers are automatically adjusted up to the level the car
would have been without the extra load. When the load is removed,
the shock absorbers automatically return to their original position.
VOLVO XC90 D5 (163 BHP)
Volvo's direct-injected five-cylinder 2.4-litre all-aluminium turbodiesel
engine harmonises with the dynamic properties of the Volvo XC90.
The very latest diesel engine technology featuring common rail direct
injection and variable turbine geometry results in alert response,
exceptionally smooth operation, remarkable pulling power and, not
l east, superior fuel economy. High torque (340 Nm) from 1750 revs
provides excellent performance whatever the driving conditions. The
engine's low weight contributes to the low fuel consumption and the
well-balanced road behaviour.SUB-WOOFER
Provides really full bass reproduction at all volumes. With
built-in 140 W amplifier. Placed behind the load
compartment's left cover panel. Available for the Premium
Sound and High Performance audio systems. Not in
combination with third row AC.
REAR HEADPHONE SOCKETS
Allows four rear-seat passengers to listen to the radio or their
favourite CD at the same time, without disrupting the car's
other occupants. With separate controls for headphone volume
and audio source. Also with controls for changing tracks or
switching radio stations.
YOU CAN EASILY TRANSFORM YOUR VOLVO XC90 INTO A MOBILE ENTERTAINMENT FACILITY. YOU CAN CHOOSE BETWEEN
TWO LEVELS FOR THE SPECIALLY DESIGNED AUDIO SYSTEM. DEPENDING ON WHICH AUDIO SYSTEM LEVEL BEST MEETS
YOUR REQUIREMENTS, YOU CAN CUSTOMISE THE SYSTEM WITH A WIDE RANGE OF OPTIONS. AND FOR THE ULTIMATE
EXPERIENCE, THERE IS THE OPTION OF A COMPREHENSIVE ENTERTAINMENT CENTRE FOR REAR-SEAT PASSENGERS.
REMOTE CONTROL FROM THE STEERING WHEEL
Makes it possible to adjust the volume, switch radio stations
and play the previous or next track without taking your hands
off the wheel. Also used for operating the integrated phone.
With illuminated buttons.
REAR-SEAT ENTERTAINMENT SYSTEM
Compact entertainment system for rear-seat passengers.
With DVD player and 7-inch widescreen that folds down from
the inner roof. Wireless IR headphones allow the passengers
to watch a DVD film, listen to a CD or play computer games
without disrupting the car's other occupants. The system is
easy to operate via menus and has a separate remote control.
( Accessory - available 2003)PREMIUM SOUND AUDIO SYSTEM
Uncompromising audio system of world class for the
truly discerning music-lover. Premium Sound
l oudspeakers and the latest generation of Dolby
Surround Pro Logic* give a unique sound experience
with an authentic sense of presence whether you are
sitting in the front or the rear - it's just like having your
favourite orchestra along for the ride.
•

1 2 Premium Sound loudspeakers
•

Dolby Surround Pro Logic 11*
•

Premium Sound amplifier, 4x70 W, plus 25 W for the
centre loudspeaker
•

6 CD changer
•

RDS radio
•

Can be supplemented with an integrated
6 CD changer, MD player, sub-woofer, separate
remote control and rear headphone sockets.
HIGH PERFORMANCE AUDIO SYSTEM
High-class audio system to meet high demands on
natural sound reproduction.
•

8 High Performance loudspeakers
•

High Performance amplifier, 4x40 W
•

RDS radio
•

6 CD changers
•

Can be supplemented with an integrated MD player,
sub-woofer, separate remote control and rear
headphone sockets.
'The Dolby and Pro Logic trademarks are the property of Dolby Laboratories Licensing Corporation.
t OptionalECC (ELECTRONIC CLIMATE CONTROL)
Maintains the set temperature inside the car, however much the
temperature outside fluctuates or the sun shines in. The
interior air quality system helps prevent exhaust gases and
odours from entering via the ventilation system, the air inside
the cabin is cleaner than the air outside.
ELECTRICALLY-OPERATED GLASS SUNROOF'
Makes the interior feel extra light and airy. Touch a button -
and you open or close the sunroof. And if the sun is too
strong, you can always close the built-in sunshade.
I NFORMATION CENTRE
Helps you to drive more economically. It shows the current
and average fuel consumption, how far the fuel will take you,
average speed and distance driven.
AUTOMATIC ANTI-DAZZLE REAR-VIEW MIRROR
Prevents you from being dazzled by headlights from behind.
REAR PARK ASSIST
Makes it safer and easier to reverse. A buzzer inside the cabin
makes an increasingly intense sound the closer you come to an
object immediately behind the car.
ELECTRICALLY-ADJUSTABLE FRONT SEATS'
Make it particularly easy to adjust the seating position. The
driver's seat is available with a memory function for three
separate settings, including adjustment of the door mirrors -
highly practical when taking turns at the wheel.
CRUISE CONTROL
Allows you to drive in extra safety and comfort without having
to keep your foot on the accelerator. Easy to operate via
buttons set into the steering wheel.
RAIN SENSOR
Activates the windscreen wipers as soon as it starts to rain or
if water splashes onto the windscreen. The system's degree
of sensitivity can be adjusted via a ring on the wiper stalk.
I NTEGRATED HANDS-FREE GSM PHONE
Allows you to make and answer phone calls
using the buttons in the steering wheel or the
integrated keypad in the centre console. You
can also read and send SMS messages when
the car is at standstill. The extra handset in the
tunnel console allows you or one of your
passengers to carry on a private conversation.
RTI NAVIGATION SYSTEM
Helps you find the fastest route to your
destination and to the nearest parking-place,
hotel, petrol station, restaurant, tourist site and
so on. Audible instructions guide you when
necessary. On the display screen, you can see
where you are and how far you have left. The
system is controlled via menus and you do not
need to take your hands off the wheel. All map-
based information covering Western Europe is
stored on one single DVD disc.
BI-XENON LAMPS
Provide you with even better low and high
beam in all conditions without dazzling
oncoming traffic. Low beam is adjusted
automatically to provide the best possible light
pattern when the car is heavily laden.
I N ORDER TO FURTHER ENHANCE THE DRIVING EXPERIENCE, YOU CAN SPECIFY A VARIETY OF SPECIALLY DESIGNED
OPTIONS. THERE IS EVERYTHING FROM VOLVO'S ADVANCED COMMUNICATION AND NAVIGATION EQUIPMENT, TO
FEATURES THAT MAKE YOUR TIME BEHIND THE WHEEL EVEN SAFER AND MORE COMFORTABLE.
FOR DRIVING FREEDOMConsideration is noticeable down to the smallest detail.
For instance, it is so convenient to get into and out of the car -
i rrespective of where you are seated.
The centre console's rear section can be simply removed to provide
added legroom for the passenger in the middle of the second row.
The middle seat in the second row of the seven-seat version features
an integrated booster cushion and has extra forward adjustment so a
child sitting in it is closer to the adults in the front.
All the upholsteries, interior fabrics and inside door handles are
allergy-tested and meet the highest ecological standards.
I

I
ECC
I nterior air quality system
Heat-reflecting windscreen
Electrically-operated glass sunroof
Cruise control
I nformation Centre
Automatic anti-dazzle rear-view mirror
Rear Park Assist
Electrically-adjustable front seats, driver and
passenger
Electrically-adjustable driver's seat and
manual height adjustable passenger seat
Memory for electrically-adjustable driver's
seat and outer rear-view mirrors
Electrically-retractable outer rear-view
mirrors with ground lighting
Illuminated vanity mirror for the driver
Integrated GSM phone
Hands-free for GSM pocket phone
RTI navigation system
PC table
Business bag
Rain sensor
Electrically-heated front seats
Headlamp cleaning system
Bi-Xenon headlamps
Auxiliary lamps
Foglamps
Engine heater, electric
Cabin heater, electric
Residual heater
Engine and cabin heater, fuel driven
Snow chains
Mudflaps, front and rear Volvo's entertainment system
with a DVD player and
pull-down widescreen display
enhance every journey for
those in the rear of the car
(accessory only).
Two people up to about
1 60cm ride in comfort and
safety in the rearmost seats
of the seven-seater version.
For even greater comfort, this
area can also be fitted with
its own air conditioning
system, including adjustable
ventilation vents.
Rear headphone sockets allow
several passengers to listen to
their own choice of music
without disturbing the others
(optional).
Adjustable ventilation and
heating vents for the rear-seat
passengers enhance comfort
and help keep ice and mist off
the side windows.

[RoyMacDonald]

Mike I have a printed hard copy of a PDF called "Volvo All Wheel Drive" which I think is on the Club pages somewhere. A few qutes from it....

"The hydraulic clutch acts as a diff lock."

When accelerating uphill...."four wheel drive is the optimum solution"

Takeoff and acceleration..."The ratio varies steplessly between 100-0% front and 100-0% rear"

Cornering....

"The rear wheels recieve more power when entering a bend providing rapid steering response.

The power is distributed more equally between front and rear when the car is well into the bend. This affords neutral steerng behaviour.

The power to the front wheels is increased as the car exits the bend, providing a degree of understeer and excellent directional stability.

This effect is becomes more pronounced the more the driver accelearates through the bend."

In normal driving the XC90 should be regularlly using the AWD system.

All the best.

Roy

[Clan]

With this system the front wheels are ALWAYS driven 100% just as a normal FWD V70 for example , when slip is detected the clutch comes in and starts driving the rear wheels not necessarily 100% depending on the circumstances an amount just to prevent the front wheels slipping .... then it eases off and if there is no more slippage of the front wheels it virtualy disconnects the rear wheels again ... all this happens many times per second ...
A new development called "Instant Traction" brings in the clutch when the car is stationary so that the car takes off with full 4 wheel drive, once underway it disconnects the rear wheels ,
a simple and effective system .
It is an oversight that there is no diagnosis if a mechanical fault causes the drive to fail .. All it needs is some software tweaking .. to put up a message " AWD MECHANICAL PROBLEM"