Anybody notice how on the superduties drive with an auto, it feels
like it shifts 4 times (b/c of the locking tq converter, I know)
but, mine quit doing that quite awile ago. I just never payed
attention to it really, today I noticed it did twice. What causes
it to not lock up, failing tq converter. And the. it didnt do it on a
short trip again today.

 

One of the criteria for an auto to lock is (usually) engine temprature, and since diesels tend to run cool you may just not be getting warm enough for the tranny to lock during a short trip. Its just a guess on my part however.