I had a Tip that was low on fluid after being swapped across a couple engines. New filter went on a couple years ago (under 3000 miles) so I didn't replace it, but just drained and added some fluid.
Here's a copy of what I posted on another forum. Don't be like me:
...Automatic transmission service on the Xbox yesterday. For the refill, you pump fluid in the drain hole until it comes out, then plug it, start the car and shift through gears, wait until the temp is 30C to 35C, then pull the plug and pump in more fluid until it comes out again. If it gets too hot before you are done, stop and cool it back down.
I wore gloves, but ended up with fluid running to my elbows.
16 quart drain pan with 36"x24" cardboard underneath and still splattered fluid on the floor.
The cheap hand pumps didn't have an elbow type tip on them. At first everything I pumped in splashed back at me. I had to hold the bottle of fluid+the pump+the end of the hose in the transmission while pumping. The pump came apart.
I rebuilt the pump with an old one that I should have thrown away. I made a 90 degree elbow tip out of a vacuum hose fitting. By the time I was ready to pump again the transmission was too hot.
A box fan blowing on the transmission took an hour to get it back in range.
Laying in a puddle of transmission fluid I tried again. The reassembled pump jammed.
I switched from a pump like the one pictured on the left to an orange one like on the right. Trying to hold it all and pump was difficult, but possible - until the bottle tipped over and spilled most of the fluid on the floor. The transmission was too hot again by then anyway.
Plug it, Box fan, wipe up mess, wash, fresh clothes, lunch ...Autozone for more fluid.
I had run out of ZF Lifeguard fluid, but know that Valvoline Maxlife meets the spec. There was a sign on the Autozone shelf "2 quarts for $16" which was a $4 savings. At the counter I looked at the receipt. Wrong charge. The manager went to check and came back with the sale sign. "This sale ended a week ago", she said. The counter clerk looked at me with silent words "Just go away now sir." No. Void the sale and give me my money, I'm done with this store, thank you.
Nearby I bought a gallon of Valvoline from O'Reilly.
Back at the car, I did what I should have done at the beginning. I dumped the fluid into my Motive brake bleeder bottle, pressurized the bottle and pumped in the fluid through the 90 degree vacuum fitting. Smooth, simple, the car shifts better than ever now.