Vehicles of that vintage originally used Freon 12, BUT, you can easily convert to 134-A. You'll need to have someone evacuate any remaining freon from your system and remove any of the oil. Some of the oil used in Freon 12 systems is reported to be incompatable with the 134-A refrigerant, but I actually haven't encoutered any. You'll need the adapter connections, but they're relatively inexpensive at most auto parts retailers, then you'll need a can of oil charge and however many additional cans your Dakota will need.
4 1/2 quarts
134 A
In my 1989 Dodge Dakota the brake light is on fuse number13 it is a 5amp it also goes to buzzer, speed control, check engine light, anti-lock warning light, and other things page 12-19 Haynes 1987- 1993 Dodge Dakota Repair Manual
75w90
Transfer case gets ATF (auto trans fluid) Axles get 75w90 or 80w90 gear oil.
ATF
***SUM'S Answer***- Your thinking a ford engine by saying 5.4L. Your dodge Dakota is a 5.2L 318cu.in. They take 5 quarts of oil.
The spring side goes towards the block.
4.5 quarts
Where the lower hose goes on the engine, it is under that housing.
Mopar ATF+4
Dot 3Dot 3