Gday OLSCHL,
are you using the 3 wiper (MG type) setup with the bundy tube and cable. I have bought for mine and fitted when screen was on and had lots of trouble getting an even movement of the wipers across the screen. This was due to the motor not being 100% secured to mounting method. There is quite a lot of force against motor
when pushing all 3 wiper boxes. Check motor isn't moving when wipers operate?
Cheers Leeroy