[Z-man]

Do you have electronic brakes and a brake controller in your truck, or does your trailer have surge brakes?

Take it out of overdrive (6th gear) when approaching a very long incline to prevent the motor from struggling, and from slowing down by 20mph.

If you are on level ground & cruising, it is more fuel efficient to leave it in high gear.

This is what I do when towing my 944 to the racetrack, and what I tow is significantly heavier than what you're pulling...