We were returning home from vacation yesterday when I experienced a strange transmission issue. We were going up a hill, the explorer downshifted to accellerate, and when it shifted back up it clunked really hard, and the "O/D OFF" light started blinking slowly on the instrument panel. I had my wife look it up in the owner's manual while we drive the remaining 50 miles or so home. Anyhow, I noticed this morning that it clunks more than normal engaging reverse from park, and drove it to the shop. They pulled codes and got P0796. They recommended I take it to a transmission shop to have the work done. In my research online it looks like the most likely culprit is the solenoid pack. I have an appt with a local transmission shop in a couple days to get the diag and repair estimate. I want to be somewhat informed about the possible issue before talking to the shop about what work needs to be done. If I bought the solenoid pack online and replaced it myself would it likely fix the issue? Does this sound like the likely issue? Any advice would be greatly appreciated. I've included a photo of the sticker inside the driver's door as well.