It's on the passenger side of the engine toward the back. It has either a red or black cap. To check the level, warm the engine to operating temperature and let it idle in Park for a minute or two. Take a lint-free cloth (this is not optional) and wipe the fluid off the dipstick. Stick the dipstick back into the tube and push it down all the way. If the fluid is low, add more (about 4 tablespoons at a time, because if fills up fast!).
Mercon Dexron III is used for automatic transmissions.
No dipstick, just filler level plugs on the transmission and the transfer boxes.
under the hood
A518 is the transmission if it is an automatic, and if it is a manual then it is a Getrag 360.
It is a completely different transmission than what was used with the diesel before.
47RE
You fill the transmission fluid on the 1988 F250 diesel at the dipstick of the transmission. You will need a filler funnel in order to keep spillage to a minimum.
I also have an f350 with the 7.3 and there is no other place to fill it besides the dipstick area use a funnel and be careful.
Automatic, yes
A518
should be a C-6
11 quart's for a diesel 10 guart's for a 94 with a old with a old dipstick