I have a 1995 ford 555D backhoe I'm asking if the 2 dipstick ports in the cab are both fir transmission because they seem to have no fluid in them but my backhoe runs fine.. do I fill it to the line while it's running?
I'm afraid you'll need an owners manual if nobody comes along with an answer. An owners manual is usually a minimum for operator knowledge. It wouldn't surprise me to find a port that is not used in that application. Many transmission housings were designed for a different application and repurposed for construction equipment use. I don't know if this continued to this model or not.
You're lucky because you are substantially low. The front dipstick is for the transmission and the rear dipstick is for the center housing (ring,pinion,brakes, planetaries and wheel bearings). I suggest you get some 134D UTF which meets or exceeds the Ford spec and fill to the full level on the stick. If the oil is dark or milky white, dump it. If your converter has a drain plug, drain it. Replace your transmission filter. If your oil is light and amber, top it off. Change the transmission filter just because ... .