Here’s how to tell if your Volvo’s AWD is functioning. No donuts required.
jimmy57 » For viscous coupling AWD in 97-2000 models you jack up one rear wheel with trans in Park and then apply a torque wrench on a wheel bolt on the raised wheel and apply force. The wheel should move smoothly at more than 60 lb-ft and not more than 90 lb-ft. If it doesn’t move then the VC has dried up and is binding.
Viscous coupling test method
- Raise the left or right-hand front wheel so that it rotates freely. The other wheels must be in contact with the ground.
- Select neutral.
- Position a torque wrench horizontally as illustrated.
- Read the torque value.
- Note! It is important that the torque wrench points towards the center of the wheel to provide the correct torque reading.
- Turn the torque wrench half a turn (180) clockwise with even torque for 25 seconds.
- The torque must be GREATER than 50 Nm ( 37 lb ft) during the entire turn.
- The test method assumes that all the other components included in the system function correctly. If the torque is below 50 Nm (37 lb ft), the viscous coupling is outside the specification and/or damaged.
Ozark Lee » The quick and dirty test is to see if the prop shaft is hooked up. If it is and the car doesn’t vibrate badly then chances are the AWD is fine. You can tell the difference driving between AWD and FWD but I don’t think I can adequately describe it. The AWD feels a bit heavier in the handling department but I don’t think any two Volvo P80 cars feel exactly the same in the steering anyway, even the FWD cars all feel a bit different when you go from one to another.
pbierre » If AWD is an important part of your circumstance, be aware that the Haldex units were a big improvement over the earlier viscous coupling AWD. That would weigh in favor a getting a 2004+ XC70 (the ’04s were the last year that came with polycarbonate headlamp lenses, which don’t show their age).
To test if the prop-shaft is working, lay your camera on the pavement, camera-video shooting upward, and drive the centerline of the car slowly over the camera….you’ll see if the shaft is rotating or not.