I assume you are saying the oil is leaking out of the
round hole at the end of the ..torque tube.. in the lower
right of the pic Barnyard posted. You should be able to
glean everything else from the literature I sent you the
link to. You fill it in the same hole you check it in. The
seal for the input shaft of the transmission is probably
bad. The link is to the CNHI parts diagrams for your
tractor. Go to the Chassis section, then to the 086
transmission subsection, number 27 is the seal. The
tractor would have to be split to replace it. Where was
the tractor stored, was it outside? I would suggest you
loosen the transmission drain plug until it starts to
drip, see if it drips water. Water may have got in the
trans and went to the bottom an caused the oil level to
go overfull. If no water there is no need to fill the trans
it will just leak out again until you fix the seal. If you are
not driving it more than 5 miles it will be fine as long as
there is a couple of inches of lube in there. You
probably have nothing of the sort, but just do not run
something with the PTO for any period with it setting
still, there is a bearing in the trans that will not get
proper lubrication in this scenario.
CNHI Farmall A online parts diagrams