People are suggesting that you add transmission fluid. I must comment it is very important to not overfill a Ford transmission. Check it once the engine has been running about 15 minutes, and make sure the level is at least a tiny amount below the hash marks. Once you climb a grade, and the transmission is warmer, your fluid will increase in volume, and if there is excess, it can puke out the fill tube, and drip onto the hot engine exhaust manifolds. This can cause a engine fire.
The transmission fluid is checked while in park, engine on and warmed up. If you start the engine, and there is nothing the dipstick, then you can safely add 1/2 quart at a time until something shows up on the dipstick. It can sit ideling for a while with only a tiny fluid level on the dipstick safely. However if it is puking out oil under the RV, the park owner might not like it so much.
You might have noise from the transmission valve body picking up air because the transmission fluid level being really low. If the noise goes away once the fluid level is corrected, that would indicate air in the system that is now gone.
Puking a pint or more of fluid while the engine idles, might indicate a bad or cracked torque converter. No need to run to the dealership for a new one, even a transmission shop will only get you a used one. One they picked out of another truck - probably at a junkyard for only a few dollars. Normally they will do nothing to the torque converter except clean it in a parts washer and sell it as a used part for $250 - give or take a few bucks.
Fred.
