I have a 2000 Durango 4.7 slt. The power steering is going in and out. I will be turning and the steering is stiff then back to normal about 3 or 4 times during the turn. The fluid is full and I can't see any obvious leaks. I am wondering if it is the pump, rack and pinion, or the pressure valve. Where should I start? Should I just replace all of them or could it be something else?
Thanks for any help.