I too thought that my motor was not working once a long time ago. In actuality, my rear hatch does not close fully on every fourth or fifth slam. The door seems shut, but it is not fully closed. Every time I use the gate, I turn the wiper on to see if it is fully shut. If it is shut correctly, then the wiper will work. If not, then it will not work. I think that the previous owner damaged the hinge by over-stressing it. The hinge alignment is just such that it does not close perfectly every time.
I have done it! It was very hard to remove wiper shaft. I thought it will be not possible and using hammer was so. I used vise BUT very carefully. Now my wiper works very fast and like new one! I think important is to repair before wiper stops forever. My stopped. If anyone needs help I will!
These things are troublesome.......... There is an adjustment on the unit that can fine tune it (with the plastic off the inside of the hatch), but if like mine it was a waste of time and I had to replace it. The dealer had it in stock (re-mfg) and said that it's a common replacement. The shaft on mine was fine. It was internal.
sorry too late already sold it, normally u can get the old one working tho, ive done 3 motors and the only reason i had to buy a new one was because i was stupid and hit the shaft with a hammer and the nut wouldnt fit on afterwards