Originally Posted by stubborn66

one of my customers was having the same issue a while back and he brought me a spring and a check valve, "ball bearing". I pulled the oil pan and on the side of the valve body there was a plate that houses a series of these check valves. I belive it was the third one back, sure enough the spring was broken. I replaced the spring, ball valve and it shifted fine.
I have not been able to find the article that he found the information in and Peach Parts was not aware of what I was looking for. Also, be carefull to get the right spring, as I understood it there were different tensions on the springs in the various positions