my truck has that stupid MDS and sometimes i drive around in tow/haulass mode. well tonight, i had it in haul *** mode and around 50mph, it stayed at 2k rpms in 4th(auto) and it didnt want to hit 5th. i sped up and let off the gas and it shifted, but it kinda bucked a little bit. thats not normal is it? even with the MDS on, it cuts in and out alot and it feels weird. truck is an 08 1500 with 19.5k on the clock. ive had 3 vehicles in the past with transmission problems and maybe its just me being worried about it. i have aftermarket exhaust too, so its very noticeable when it goes from 4 to 8 cyl.

 

I have the same problem but only when it is cold. I have an 08 1500 with 16k and it bucks good when put in reverse and drive in the cold morning. Other than that, it never does it. I chalked it up to being cold, I am probably wrong though.

 

well, with the remote start, its usually warm by the time i left for work in the mornings. but now, its in the garage and doesnt idle in the driveway and **** the neighbors off haha. but im hoping its just the cold. ive only had it for 6 months, so i guess we'll see what happens when it warms up.

 

Tow haul should lock 5th out so nothing to worry about.

 

yeah, tow mode locks out 5th. The rpms is nothing to worry about. The "buck" is probly your downshift. It happens. It feels weird and it sux, but the stock shifting is so jacked up on these things, its ridiculous. Especially with the MDS.
I got my truck and within a week, I bought a Superchips so I could disable the MDS and patiently await the upcoming customized shifting. Best thing Ive got for the truck so far. You should check it out.