Windshield Wiper/washer Linkages problems of the 2000 GMC Sonoma

Passenger and driver seats in my 2000 GMC Sonoma have seat positioning controls and locking mechanisims that do not always lock properly and/or get jammed up and have broken. A friend was sitting in the passenger seat and it failed to lock into place to keep it from sliding forward. I adjusted the bolts that fasten the seat to the floor of the vehicle to help 'realign' the seat frame so that the mechanism that keeps the seat from siding front and back would keep the seat locked into position once the seating distance is set. Also, the reclining handle on the passenger side broke off, not allowing for seat back support angle adjustment on the passenger side. The driver's side seat back support adjustment lever often 'sticks' or 'locks' into position. . . . Not allowing for seat back rest adjustment. Rear differential sometimes locks up and or slips and shakes and makes noise. . . Especially when sideways force is applied. . . Such as when turning in a curve or circular fashion with the vehicle in motion. Both tailgate support cables broke on the truck. Front driver's side bearing had excess wear and had to be replaced at 65 000 km. Driver's side wiper arm got dislodged from the shaft that turns it and was knocked out of position on 2 occasions. Power steering fails for short intermittent periods when the vehicle is first started from a 'cold' and 'warm' state and the steering becomes stiffer and less responsive. Most noticable at slower vehicle speeds.