Here's a simple method to make one. Take 10 mins.
Here's what I built. I had a clear/translucent bucket. It has a top that snaps on (also has a handle). I drilled a hole on the top and attached a 1.5'' PVC pipe fitting, on the opposite side of the top I drilled a small hole and attached 2 1/4'' barbed fitting with a connector, so that one is on the top and the other on the bottom. I also bought 10' of clear 1/4'' hose and cut a small piece to that the bottom barbed fitting to the bottom of the pail. Put the lid on and connect the top barbed in to what you want to suck/pump out. Insert your shop vacuum in the 1.5'' PVC connector and the fluid will be sucked through the hose and into the pail.
I tested it with water and it emptied a pail quicky and since trans fluid is not to thick it sould work equally well. I think it will work for thicker fluids also, just slower.
Total cost about $6. The shop vac never ingests anything since it's separted.