On my truck, I use the "tow/haul" mode and really like the mapping of the shifts. Is there any harm using this mode for everyday driving, or should I stick to the default setting? Thanks.

 

No harm at all. In fact, since your tranny will be doing fewer shifts it will probably be better for it. When OD trannies came out it was common practice/procedure to drive around town in D and not OD to extend the life of the tranny.

Your mileage will suffer a little, especially at highway speeds.

Ooops, I just noticed you have a 2005 which has a different tow/haul button and I can't remember what the difference is. So I'm not sure if the above info applies.

 

The shift points are not that different, if at all, when T/H is engaged. You will not get torque converter lock at lower road speeds when T/H is engaged, and once it locks it will stay locked as you slow down, I believe down to 18-20 mph. You will feel the downshifts during this time. Drive around town with T/H engaged and you'll most likely just get irritated with the poor shift quality and decreased fuel economy, IMHO.