It is just a little hand pump that threads onto the top of a quart container. The discharge has a hose connected to it that can be put into the fill hole of the tranny. You just push the lever down, a little oil goes into the hose and it pops back up. Very simple. I use this since it is almost impossible to fill these with 3" exhaust right on the side of the tranny.
The real use is for on the lower unit of a boat motor. The hose has a little threaded fitting that will screw into the lower unit bottom drain hole, you fill from the bottom and vent out the top, when the oil comes out the top vent, you re-install the plug and then remove the lower hose and reinstall the plug.
The only real problem is when you get to the bottom of the container, it does not get all of the oil out, you have to refill and pump somemore.
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