Just got back from a long run to "le Mans" and back and noticed that when doing 60 & 80 mph and going up an incline the box starts to "hunt" as if it's not sure what gear to select. It only seems to happen about 45 minutes into the journey from cold, maybe overheating ? or torque converter ?
Standard auto box, ie not sport
Its had all fresh oil & filter etc.
This is the first long trip i've taken it on, never been more than 40 miles whilst i've owned it
Any ideas appreciated.