I was having similar problems with my 47RE and replaced the governor solenoid, sensor, accumulator spring and speed output sensor in the trans and all fixed now. Pretty easy job but you have to drop the pan. Here is a link to the kit for the 46RE. I also added a drain plug to the pan in case I ever need to drop the pan again.

http://www.cascadetransmissionparts.com/46regovernorpressureservicekit2000up.aspx