Hi all. I've been having an intermittent issue with my Mazda 6s's automatic tranny. Sometimes when I'm in 6th gear and I depress the gas pedal to pick up speed I'll feel what's best described as a light bucking feeling. Almost as if the tranny wants to downshift, but doesn't. If I depress the pedal more and with a little more oomph the tranny will then shift fine. Now this doesn't happen all the time. It seems to occur when there is a slight incline or hill.

My Mazda has just shy of 70k on the clock. I have changed the fluid with synthetic at 30k intervals. I'm really concerned that the tranny is going to give out sometime soon. I was hoping somebody could shed some light on the problem and perhaps suggest a way to prevent what may be further deterioration of my transmission.

Thank you for your help, it is greatly appreciated.