Reading codes set by the vehicle’s computer is always a good practice and often will lead you directly to the issue or very close. There are auto parts stores that will read and erase the codes for you.
Your cruise control may just have a blown fuse or relay.
First, I would focus on some basic transmission components. There is a vacuum hose running to the transmission. Make certain this vacuum hose is not deteriorated, cut, split, cracked, etc. Unfortunately, it is not easy to access for inspection. Look at your transmission fluid. Low, overfull, or extremely deteriorated fluid can cause such unusual behavior. Follow your manual to perform the correct steps to obtain an accurate transmission fluid level reading. The fluid should have a semi-sweet smell and should be reddish in color. Darker almost used-oil like transmission fluid should be handled accordingly by a professional. Some recommend a flush and fill, others would tell you to only replace what drains out after dropping the transmission oil pan. They may tell you that your transmission is broken in this case as well. Especially if the situation has not improved after some time or is consistent.
This could also be a sensor issue. The crank shaft position sensor is not only used for timing but is used by the transmission as well to know exactly when it should shift to the next gear. Typically if this sensor has failed or is failing, you will have a code set by the computer and on occasion the vehicle will not start at all. I have experienced a faulty crank shaft position sensor that caused a poor idle and a bit of sluggishness while driving but no engine codes. It took me quite some time to figure it out but after replacing this sensor, the idle returned to normal, the Durango was much more responsive to the gas pedal, and it shifted perfectly afterwards.
The rain is often a problem with the Durangos of this year. The original poorly designed windshield cowl leaks and allows water to run all over the top of the engine. Water and electrical components do not work well together and the resulting shorts can cease function, disable, or cause other electrical components to fail or send the wrong signals to the PCM. I believe this and heat are also responsible for causing frequent ignition coil failure. If your Durango is equipped with a sun roof, the water drain piping often will clog from sticks, leaves, dirt, etc and the water can leak out and down the A pillar directly into the junction box located to the left of the driver, near the floor. Similar to a fuse box and contains fuses. The junction box on my 04 Durango was nearly destroyed by water and was full of corrosion and rust causing the circuit board to de-laminate and the pins for the CAN bus(the module communication hub) were corroded so badly they were just gone. In this case I had to clip, splice and solder the wiring together.
I hope this was helpful!