New to 4x4 and towing
 

Two quick questions. First, what is top speed while in 4x4 high. Second, is it ok to have it in overdrive while towing a travel trailer if you will be on highway at 70 mph?
These questions are not for use at the same time...:no:

You can go as fast as you feel comfortable in 4hi and you only need to turn overdrive off if your truck starts to struggle or start hunting for a gear.

leave the OD off when towing something as heavy as a travel trailer.

It's an ultra lite 30 ft weighs 5500 lbs. I am just wondering about gas mileage with OD off for 3 hr drive...

I tow a 8.5' x 20' enclosed trailer weekdays, weighing in somewhere around 7000 pounds more or less. I do mixed driving, mostly in town but highway too. I never really take the o/d off, and the truck seems to do pretty well. I have been towing daily for the past 4 years, used to be a 6' x 12' - new trailer about 4 months ago. However, I did have to rebuild the transmission at that same time - actually went out less than 10 minutes from my destination after a 9 hour drive bringing the new trailer back from Georgia. The transmission tech said that the towing had little affect on the trans going out, and that mine was actually one of the higher mileage 150s of our generation he had seen in for a rebuild. Maybe this helps you. Also, max speed in 4wd is mandated in the owners manual I'm pretty sure.

i think you can go as fast as you want in 4x4 but after 55 mph you cant switch in or out of 4x4.

I wouldnt worry about a 3 hour drive leaving overdrive on unless you have many hills then turn it off.

my transmission guy says od is only needed to be off until you get to 65 or so. so good and into over drive. for loads more than 3000 pounds leave it off till your on the highway and cruising. and keep it off on hills on the highway.

the tow/haul mode on chevys keep the od off till 65 exactly then it lets it go to od.

so any load less than 3k dont worry about it, more than 3k leave it off till 65 or so

It is also important to pay close attention to how your truck is shifting and handling the load. The majority of my driving is under 65, and I never hit the o/d off button. Shouldnt really be going into o/d at those speeds. If you feel you truck jumping between gears then yeah, but it shouldnt. I do a lot of around town stop and go driving as well as highway, and my truck pulls the load very well, even with the 4.6 and 35s.
Again, this is with a ~7k enclosed trailer 5 days a week.

Thanks for all the feedback guys, it helps out alot. I never go over 55 in 4x4 high btw, just wanted to know if that was to fast. Again thanks for the feedback.. :)