Re: TDI power steering pump noiser than other VWs? (spongebob_squarepants)
I believe the pump is the same. If you are only hearing it on u-turns maybe it might be related to the CV joints on the suspension. The 5 speeds have true cv joints on both ends of the drive shafts while the automatics have cv joints at the steering hub end and tri-poids at the transmission side.
Since the tri-poids are not true CV's the rotational speed of the drive shaft on the output side changes up and down as it rotates. They are still common today because they are cheaper to build and simpler.
With tri-poids and other non cv joints like u-joints the greater the deflection angle the greater the rotational speed differences. This effect is cancelled by putting an identical tri-poind or u-joint on the steering hub side.
The down side of this is that cv joints can be used at much greater deflection angles than the other joints. This is why the VW T5 van can turn circles arounf the Chrysler minivans even though some of them have shorter wheel bases.
What I am leading up to is this...
VW uses tri-poids on the inner half of automatics to keep the cost down and cv's on the outer part to keep the turn radius the same as the 5 speeds. The rotational differences are absorbed by the torque converter at lower speeds and generally people don't use high steering angles at speeds where the converter locks up. The uneven loading will cause some additional noise in the drive line however.
Of course all of what I have mentioned here is pointless if the noise you are hearing is caused by the power steering pump stalling out because you have turned the steering wheel to its stops and the hydraulic fluid has no where to go. With the car stopped and engine running turn the steering wheel all the way in one direction. You will notice additional noises from the system if you hold the wheel against its stops compaired to letting go of the wheel after you have turned it as far as it will go. This might also be part of the noise you heard.
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I believe the pump is the same. If you are only hearing it on u-turns maybe it might be related to the CV joints on the suspension. The 5 speeds have true cv joints on both ends of the drive shafts while the automatics have cv joints at the steering hub end and tri-poids at the transmission side.
Since the tri-poids are not true CV's the rotational speed of the drive shaft on the output side changes up and down as it rotates. They are still common today because they are cheaper to build and simpler.
With tri-poids and other non cv joints like u-joints the greater the deflection angle the greater the rotational speed differences. This effect is cancelled by putting an identical tri-poind or u-joint on the steering hub side.
The down side of this is that cv joints can be used at much greater deflection angles than the other joints. This is why the VW T5 van can turn circles arounf the Chrysler minivans even though some of them have shorter wheel bases.
What I am leading up to is this...
VW uses tri-poids on the inner half of automatics to keep the cost down and cv's on the outer part to keep the turn radius the same as the 5 speeds. The rotational differences are absorbed by the torque converter at lower speeds and generally people don't use high steering angles at speeds where the converter locks up. The uneven loading will cause some additional noise in the drive line however.
Of course all of what I have mentioned here is pointless if the noise you are hearing is caused by the power steering pump stalling out because you have turned the steering wheel to its stops and the hydraulic fluid has no where to go. With the car stopped and engine running turn the steering wheel all the way in one direction. You will notice additional noises from the system if you hold the wheel against its stops compaired to letting go of the wheel after you have turned it as far as it will go. This might also be part of the noise you heard.
