Some of you guys may know or may not know about the lugging when you shift gears on these more particular VP trucks. The issue is that a manual operating system causes this. Good news if you have a Smarty Tuner, you can fix this. Here's the information sent by one of my customers back to me thought I would share the reply.

Just thought I would follow up on an issue we had discussed regarding my VP44 Cummins shuddering and loping at idle in gear. I already had a Smarty S03 handheld tuner, so I contacted smartpros.com for a recovery file. I verified the vin out of the ecm with my scan tool, and used a mopar vin decrypter to confirm it was indeed a manual transmission. I provided the ECM VIN to Smarty Pros and told them I wanted an automatic recovery file, and it was currently a manual. Cost $150 , and you load it just like you do firmware updates the handheld using a win based pc. The truck was immediately fixed!!!  A couple of notes I might add to anyone doing this... 

1) Keep the key in run from the time you connect, till it's done (it does not recognize the off first method of normal tuning if someone is used to using a Smarty S03) 

2)You can use the ecm stand alone (swaps) and do not have to have the abs/bcm as they tell you  

3)Be patient. Smartypros.com responds via email, and they only seem to reply 1-2 times a day 

4)Be very very clear on what trans the ecm is currently and what you want (keep repeating yourself, lol they don't thoroughly read your request the first time)