I've been shopping for both 04 and 05 trucks. Seems the "tow/haul" on the 04 locks out overdrive, but on the 05, it doesn't. I like to lock out overdrive myself at times, and wonder how it would be letting the computer decide between 3rd and 4th gear (which an 05 will do). I don't like my transmission shifting back and forth, and I don't like that "dead pedal" feeling of trying to pull grades in overdrive. Any of you towed much with an 05 auto? Is it "smart" about which gear to be in? I will be towing a 9000 lb. fifth wheel.

 

If you want smart, get the manual.

 

He's right, when you get down to it. I can tell you this: I towed about 4000 pounds, or a little more, with my 04.5. I have an auto and the 3.73's, and I left it in overdrive. Even with the converter locked, it had no problems gaining speed on moderate hills w/o flooring it. These motors make so much torque that you might very well find that you can pull 9000 pounds up reasonable hills with an auto w/o hunting, especially at interstate speeds.

 

Just pulled my 34 foot 5th Wheel Camper (12,000 pounds) with my new 05 truck. I too was disappointed with the way the transmission works. I was driving on a curvey, two lane road. At 50 mhp (about top speed on this road) the transmission was shifting to overdrive with the tow/haul turned on. The engine rpm's was only about 1,200 to 1,300 after it shifted. Consequently the engine was bogging down and vibrating. I would turn the tow/haul off and then on again and the transmission would shift out of overdrive making the truck drive normal again until it then automatically shifted back into overdrive. I thought there was something wrong with the tow/haul feature allowing it to shift into overdrive with the tow/haul turned on. However, based on your comments, I guess this is the way the tow/haul works on the 05's. What a bummer!