I have the common problem that the shifter won't always go into park and then the truck won't start except in neutral. This has been getting progressively worse over the past year or so.
I found the two T30 torx head bolts behind the dash near the steering column that are frequently referred to as being the problem, but they were both torqued down soundly. I don't know where to go next with this. I would appreciate help, please.

 

Thread moved to E series forum.

Good luck with your van.

 

On a 2013 E450 the neutral safety switch is located on the side of the transmission not the steering column.. They have been known to come loose or just wear out preventing the truck from going into park. You can find videos on youtube on how to go about checking and adjusting it properly.

 

Several reasons
Check under the dash, above your feet, the shift cable to column bracket (with the 30 torx bolts that come loose)
That is the shift lever attachment point to the shift tube.
It is the most common IMO
Cracked ready to break shift tube is common
Frayed shift cable is common

 

There is a plastic bushing around the shifter tube, if you have play, get ready to replace it, bushing is $5, the fun comes pulling it apart to replace it.

 

Some suggestions here are off the mark quite a bit, others good places to begin.

From my own experience with the shifting cable its possible its a big part of the problem but I would also be interested knowing if the shifting tube detent plate inside the steering column inside the cabin condition? Inspecting and/or maintenance does require dropping the column complete with steering wheel and air bag still in place---negative battery disconnected for about 15 minutes prior to that operation.

Good luck sorting this out---I'm confident its not that complicated or expensive to repair!