I want to thank all you good folk who made suggestions.
I thumped it and banged it and jerked on the 'T' handle, all to no avail.
I reseached some of the older threads in TDR, but they were no help.
I'm going to take it in to my local Dodge dealer and let them do whatever it is they do to fix it - at $65 an hour + some $70 for a new cable + a rental vehicle while they fix it.
Fortunately my faithfull truck doesn't use any fluids so I am not worried about not being able to check the oil or transmission etc - even though it's got 135,000 miles.