In the mountains, when starting out to go home downhill from a dead stop, its in normal drive mode. I normally turn on the Tow/Haul and then pull the shifter over to start dropping down from 5th gear. I do this for engine breaking going downhill. (I usually go down hill in 3rd) However, it goes from Drive directly to 2nd gear. You would think it would go to 4th first and then I would manually take it down to 3rd. Does it have something to do with my speed? Is it trying to match a gear with my low speed starting out? If so, this truck is smarter then I give it credit for... Anybody else have this happen? This normal?

 

It's normal. When you first move the shifter lever, it will go to the gear you are in at the time. Try it when not moving. It will go into 1st.

 

Interesting, thanks.

 

I'm towing my 5th wheel with my 2006 cummins 3500 and I'm in tow haul. I have to start braking and when I get down to about 45mph my trans does a downshift. But soon after it shifts up and I start gaining speed.
How do I maintain the trans to a speed of 45 with out braking?

 

pull the shifter out of drive and put it in 2nd or 3rd gear

 

Thanks for the reply. I thought tow /haul was supposed to handle my speed down hill automatically. What good is it do if I have to shift manually?

 

your motor can only do so much. let me see if I understand what you are asking....you have truck in tow haul and you are going downhill. so if you are in 4th gear then you hit the brakes to slow down to 45 and it shifts to third to get the rpms high on the motor so that it is using the motor to maintain speed. then you release the brakes and it shifts back to 4th and starts gaining speed again. If that is the bulk of it (and i was just throwing out gears to make a point) then I dont think your tow haul is working right. It should hold the gear until you start to press the gas again to speed up. But as I said before, if the hill is too steep or the load is too heavy and the motor cant keep speed by itself then it could shift to keep from hitting the rev limiter.