noisy cv joint

[A bear in his natural habitat <burden@rhett.enet.dec.com>]

A few days ago my wife complained about a banging noise from the back of the 
car.  It seemed to be loudest at low speeds.  I looked under the car and found 
all 6 bolts on the driver's side inner cv joint backed off.  I tighted these and 
the noise quieted down a bit.

Yesterday she complained again...  This morning I pulled the halfshaft off and 
cleaned up the inner joint.  As I rotated the joint around I could feel a little 
grinding one way and a slight bind another. About 75% of the time, it moved 
smoothly, but there certainly was some damage.

Taking the cheap route, I simply repacked it with cv joint grease and bolted it 
back up.  On the 16 mile trip to work, it was quiet most of the way, but made 
some banging going slowly through the parking lot around corners.  Hopefully I 
have diagnosed this properly and all I have is a bad cv joint which is easy to 
replace.

Why would it only bang at lower speeds?  Are the cv joints the same as a Bug?

Thanks
Dave

'71 SQB
'83 Rabbit diesel
'85 Jetta (gas)
'85 Jetta (diesel)