Try steerandgear.com
its under the steering column
On the internet - Google 1984 Dodge D100 PU.
7700
Spline end
one on the cross shaft from the frame to the engine
The manual for mine says 22 gallons or optional 30 gallons.
i have a 87 but i think they are the same. mine is located right below the steering column.
It is under the housing that the upper radiator hose hooks to.
Find a donor D100 that has P/S if that is possible. Disc brakes kits can be purchased. Click the link.
According to the owners manual: with filter change 1.4L (1.5qt).
The D100 is long obsolete
under hood,Drivers side firewall or inner fender. 4or5 wire plug with a screw in it to hold it.