My work had one of them several years ago. I was actually surprised they only had one Duramax GM van. They have several of the Sprinter based vans, but those tend to need a new transmission at 128,000 miles.
Most of the fleet was Ford E-250 and F-350 pickups. A few GMC trucks.
The reason Ford stopped putting the diesels in the vans was lack of cooling ability, compared to the trucks.
Fred.