If I am correct, there is no need for any kind of sealant in the area below the screw holes. The trick is to have the screwed joint at 10 or 2 o'clock to the top of the axle, don't over torque anything to the point of distortion. Drain and refill the trans with 80 or 90wt. trans oil. drain from the bottom, fill from the left side, it's full when it starts to run out of the filler hole.
Changing both boots although only one has split. CIP1, the original VW boots.
Correct?