I found it easier to just lock out 6th gear when towing here in the North East cruising through Vermonts green mountains and the White Mountains of New Hampshire. When I towed our new Outback 292bh(7500lbs) the first time I just hit the tow haul button and off we went. But when we hit the hills it seemed to down shift and up shift way to many times between 5th and 6th for my liking. Once I locked out 6th it will cruise along at 2000-2100rpm's all day and only downshift to 4th on the very steep grades. And depending on the amount of steep grades I average 9.8-10.6mpg. So I have no complaints and this is still the best truck I have ever owned!