From what I can tell the tranny pan was removed because it looks like a newer gasket. The front seal I cant tell but id have to say original. The tranny does have a fair build up of oil around the bottom though when the motor was spotless.

 

I didn't think it was in the truck yet. I'd just be suspicious.

 

no the 70s vans had a short dipstick and a "TRANS OIL LEVEL" lite on teh dash before they started with the mile long dipstick and tube; used to be you had to take the doguouse off the inside of the vans to access tranny to add fluid.

 

My 1981 diplomat motorhome has that exact same sender in it. Was put it from factory. Don't remember if it's for the fluid level or temp. They put it there for idiots/ people who rv but don't know squat about mechanics.

Edit: sorry my motorhome is a 1980, my truck is an 81