Dominator Kreepy

I have had a dominator for about 1.5 years now and the gears have gone 3 times. I was told that I need to check the pressure suction settings, which I diligently have for the last 6 months but again the plastic gears have gone and it just turns in circles. This is the 3rd time , it literally lasts 6 months if that before the gears go. Great at cleaning but it shouldn't cost me R 600 every 6 months to fix.