I checked Bentley but can not find the dip stick on the transmission.
The plug in the filler tube looks different (no pull ring) and I was
not able to remove it.
There is no dipstick on your van. You can retrofit one.
www.europarts-sd.com carries a kit.
Also, would it have to be topped up through
the small tube in the front?
Yes. There is a cap that pulls out of the fill tube. There should
also be a red retaining clip that holds the cap in place.