Is it working ok in reverse? My 2000 has the 3 speed auto and if I let it sit for several days, the torque converter will drain and it will do this in reverse until the pump gets the converter full again. Mine has also done this in the forward gears. I read on the net, may have even been here that there is an o ring seal that will shrink in these trannys and cause this. Also have recently read that it could be a bad solenoid. Anyway, for mine a 3 of my friends, the fix was a half bottle of Blue Devil Transimission stop leak. After a couple or 3 days, the problem should go away if it's the o ring. If it doesn't go away, probabably something else. I would check the fluid level before I did anything and maybe also change the filter and fluid if it hasn't been done in a while. Good luck with it.