Why is Volvo's AWD system so delicate?
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Why Were Gen 1 AWD Systems so Delicate?
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dcarlson12
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jimmy57
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The 2002 S60 AWD and all 2003 and later use a hydraulic clutch system made by Haldex/Borg-Warner.
There are 4 versions through today. The first two have a mechanical pump that is active only when there is wheel spin with an electric pump that keeps clutch pack free travel eliminated but is a low enough pressure to not transmit any torque through the clutch. The system is not sensitive to tire size differences as the pump will go too slow and there is a pressure regulator valve that is electrically controlled that can dump fluid even with wheel spin. The coupling has to be able to be disengaged when stability control and rollover control need to apply selective brakes without the AWD system fighting it.
The 3rd system is similar but adds a beefier pump and a higher static pressure to send a bit of torque through clutches. This what Volvo calls "instant traction" as there is almost no wheel slip before it engages. Instant traction was first on P2 R's and the XC90 V8.
The latest sheds the mechanical pump altogether and uses a high pressure electrical pump so it is lighter and simpler.
There are 4 versions through today. The first two have a mechanical pump that is active only when there is wheel spin with an electric pump that keeps clutch pack free travel eliminated but is a low enough pressure to not transmit any torque through the clutch. The system is not sensitive to tire size differences as the pump will go too slow and there is a pressure regulator valve that is electrically controlled that can dump fluid even with wheel spin. The coupling has to be able to be disengaged when stability control and rollover control need to apply selective brakes without the AWD system fighting it.
The 3rd system is similar but adds a beefier pump and a higher static pressure to send a bit of torque through clutches. This what Volvo calls "instant traction" as there is almost no wheel slip before it engages. Instant traction was first on P2 R's and the XC90 V8.
The latest sheds the mechanical pump altogether and uses a high pressure electrical pump so it is lighter and simpler.
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matthew1
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Beautiful explanation.
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1998 V70, no dash lights on
1997 850 T5 [gone] w/ MSD ignition coil, Hallman manual boost controller, injectors, R bumper, OMP strut brace
2004 V70 R [gone]
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Also -> Amazon link. Click that when you go to buy something on Amazon and MVS gets a cut!
1998 V70, no dash lights on
1997 850 T5 [gone] w/ MSD ignition coil, Hallman manual boost controller, injectors, R bumper, OMP strut brace
2004 V70 R [gone]
How to Thank someone for their post
Indeed extremely delicate. My AWD on my 2011 Volvo XC60 T6 also gave up. It went bad at 90,000 miles. Sad because it is a nice car. It used to drive so nice. I took it to the dealer. Parts alone -to fix the AWD- cost US$9,000 (US$4500 final drive, US$4500 clutch). I called Volvo with the hope their engineers work on a new AWD design.
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