96 Lumina wiper motor install

[sbriar]

I am on my 3rd wiper motor within a week, the first motor I put in only lasted a few minutes so I thought maybe I just got hold of a bad motor, after I put the second motor in it also quit working after I turned on and off a few times, I think the worm gear is stripping out because the motor shaft (where crank arm attaches) does not rotate anymore.
I thought my problem may be that I was connecting the crank arm onto the motor backwards (180 degs). So on the 3rd motor (thank god for lifetime replacement) I attached the crank arm 180 degs from the previous two motors so that the crank arm is underneath the transmission assy, this makes perfect sence because the motor now has to work less to rotate the linkage. This works well except for one problem, the wipers run backwards, the wipers park in the up position not in the down position like they should. Any Ideas before I ruin this motor also, I don't think the parts store would go for a forth motor.
Help me Please!