Transmission Problem in 03 47RE AUTO

[MTenore]

Here is my problem...I have a 2003 Ram 3500 sw with 52k miles. Auto tranny 47RE. Have an oversized tran. pan and one on the rear trans.
I carry a large camper usually 9.5 S AND S.

For the last yr. when I start out in Park, and shift to Drive or Reverse.. NOTHING happens. I Can rev the engine lightly but the gears do not engage; I shift to P or R or Low range and it still does not engage. After a bit, it decides on its own to shift.

This only happens occasionally. Tran fluid is at right level and no bubbles etc.

Need an adjustment or//// they have not been adjusted. I bought it used at 9k.

any help would be appreciated,

Mike