AWD testing - apart from prop test?

[jgjones095]

Get 4 axle stands and a jack then raise the car off.the ground.

[RFW]

Just curious as the MOT said that felt like it was in 4WD when he was manoeuvring it forwards at full lock. I thought maybe full lock presents enough of a speed differential on the front wheels to make her think that a front is spinning and to transfer some torque to the rear?

The first check I'd make is that all four are the same make, size and tread depth to confirm there's no false indication of 'slip'.
Once certain of that then change the Haldex oil and filter to get rid of all the black sludge which tightens up the coupling regardless of electrical commands. Does anyone have a copy of the bulletin to Police workshops which describes the condition ? Many other vehicle brands schedule haldex service as a routine item.

[Tannaton]

[QUOTE=RFW;2468787]Just curious as the MOT said that felt like it was in 4WD when he was manoeuvring it forwards at full lock. I thought maybe full lock presents enough of a speed differential on the front wheels to make her think that a front is spinning and to transfer some torque to the rear?

The first check I'd make is that all four are the same make, size and tread depth to confirm there's no false indication of 'slip'.
/QUOTE]

The system is clever enough that they tyres don't matter - even if you have a space saver spare fitted.

[Tannaton]

Originally Posted by robsterpaterson

Sorted, AWD seems to be fine. However, I used to own a Golf Rallye from 1989 and it had Haldex. The only time that it was in permanent 4WD was when it was in reverse so I'm wondering if the Volvos are the same???

Depends on the model year, I think there were three different version of Haldex fitted to the XC90, but later versions (Gen 3 and later, marketed as "instant traction") engaged the AWD system when setting off from rest up to around 5 mph regardless of throttle or wheel slip.

[robsterpaterson]

Hmm, this was all low speed...

Ultimately, I know that it works at least!