Gauges, etc.
I have a 2006 with auto transmission also. One of the first things I did when I bought my truck new was add three gauges--EGT, Boost, and Trans Temp--mounted together on top of the dash in front of the driver's seat. I chose Isspro gauges, which matched the factory gauges quite nicely, and bought the gauges and mount from Genos. If you call and tell them what you doing they will not only give advice and send the guides they have prepared on how to install, etc., they will also make certain you get all the parts you need to complete the job. They know what they sell and will make sure it fits and comes with even all the little parts. Later, after my in-dash tachometer failed, I added a tach and fuel line (not common-rail) pressure gauge in a steering wheel mount, from Genos, of course. I just checked and Genos still shows both mounts on their site.
I also want to comment on your statement about accelerating from 40 mph. Maybe this is a case of the words having a different meaning for each of us, or maybe my truck has a problem, but at 40 I'm most likely to be in 3rd, not OD. I need to reach about 46 or 47 mph to be able to stay in OD. If I do manage, by being on relatively level ground and gentle driving, to get into OD at 40 and accelerate at all my truck will downshift. I have a Smarty POD, not Smarty Jr., and don't know if this makes a difference.
As long as I am mentioning differences I should also mention I have put the factory fuel pump into reserve status and have installed a FASS Titanium fuel pump instead. With the FASS I now have 3 micron filtration ahead of the factory 7 micron filter and a total of 3 filters in the fuel line.