93 transmission problems

I have a 93 intrepid (3.3L) with 180K miles. Tranny was rebuilt about a year ago and has worked fine up to now. The car starts off fine and after a few minutes of driving it starts to whine. Bump it up into neutral and the whine increases with the RPM's. It still pulls fine at this point but within a few more minutes the tranny starts slipping. it will last for a couple of seconds and then pull again. Sometimes the whinning goes away but not for long. I also noticed that when it starts doing this is doesn't seem to shift into overdrive. I've had different opinions locally. (torque converter, pump, solenoid,...) any other opinions???

well, it sounds like your oil pump is low. Check the fluid level on your dipstick to make sure you have enough fluid in the transmission.

The fluid level is full. The whining reminds me of when the pump was going out in my old ford truck. The wierd thing is that it doesn't whine all the time and it only slips for a few seconds before catching back up.