the trans fluid plug is a screw in plug near the oil dipstick. Remove that plug and it will have a dipstick made into it. That is the Transmission Fluid reservoir.
there is a Allen screw on the side case fill until it begins to run out.
hd transmission lube ask your dealer
The Oil Filter is located under the bike just behind the transmission.
1977
Three quarts of motor oil, one quart of primary oil and 24 ounces of transmission oil.
24 oz is what most take do not over fill or it will bust your seal
39 mm
you can find it in a clymers manual #m420
On the forward side of the transmission end cover on the right side of the bike there's a round plug with a hex-shaped hole in it. That's the filler cap.
There is NO WAY possible
You should only use Harley transmission fluid from the dealership. It's engineered by Harley for their transmissions.
You fill the transmission through the dipstick