Went to tractor supply yesterday and got hydraulic oil that is Allison rated. It was on sale.
I already had the pan filter and pan gasket.
Started this morning by letting it drain for a few hours while I got some other stuff done(opening our pool up). I think went underneath and checked things out to ensure that is all that was leaking. I found the PTO cover was leaking as well. So I called up the semi-local(30 minutes away) to see if they had the PTO cover gasket. They did... $7.50.
So I raced up there, got it, and came home. Pulled the PTO cover off, cleaned it, put the new gasket on and torqued it down. Then went underneath, removed the dipstick tube from the pan, and removed the 20 or whatever bolts from the transmission pan. Several were only hand tight, so perhaps that is why it was leaking. Got the pan out, emptied the remaining oil out, and went to town cleaning it. Swapped out the spin on filter. Realized the gasket was going to be a PITA, so I went to Napa, and got some gasket cement to hold the gasket in place, also picked up a grease zerk for the front hood pivot. Old one broke off, so I have to extract that.
Put the gasket cement on and got the gasket positioned on the pan. Got it all bolted back up, got the dipstick tube threaded back on, and went to town filling it up.
Started with 3.5 gallons or so, and then started her up. Let her idle for about 30 minutes, then ran it through all of the gears. Checked the level...WAY low. To my surprise, I ended up adding pretty much all of the 5 gallons of hydraulic oil I bought. There might be a quart left in the bucket, but the transmission is right at the full line now...perfect.
No leaks...(knock on wood). Can't take it for a drive yet, I don't have the drivers seat back in the cab yet. I'll try getting that painted tomorrow.
Tomorrow I have to degrease everywhere the transmission leaked, and made a huge mess(mainly the crossmember). Have to take the oil out to the dump and dump it into the recycling container. Next up is changing the engine oil.
I am exhausted. It was 95 degrees out today and was outside working from 9AM till 8PM.