Originally Posted by avalys
This is not correct.
The transmission has 6 different ratios. It will always shift into the highest gear on the highway. How it displays that in the EVIC is a different question. But the transmission will definitely always shift to the highest available gear when it can. To do otherwise would be silly.
To answer the problem in the OP - wait for a tuner, which should not be long at this point. Engage sport mode and tow/haul mode, or manually select gear "3" for cruising around town.
I don't want to get in a pissing match but this is one of the sources of my information.
The 45RFE, 545RFE, and 65RFE automatic transmission for Jeeps and Rams
"The 65RFE only has six forward gears in ERS/AutoStick mode or kickdown mode; it is essentially a software and name change, which allows people to reach the “prime” gear via ERS as well as than kickdown. An internal Chrysler communiqué to dealers summarized the change in a similar fashion."
"On 65RFE, 3rd is only accessible via kickdown in some situations and use of manual override."
Key word above is "only" which supports 5 forward speeds under normal operation in "D"
A true 6 speed transmission would have 6 separate forward gears and a reverse gear, not something that requires "disclaimers" or special operation to use/shift thru 6 forward gears.
Here is another thread with some more info. I wouldn't call a transmission that completely skips third gear while in "D" under normal operating conditions a "six speed transmission"