After reading some previous threads about coolant system additives as "fixes" for the infamous blown head gasket problem, I thought I'd share a different story.
"Mouse Milk" is a term used for any "mechanic in a can" item.
My 2000 OBW had a slight case of hesitation when first put into any forward gear (auto, 4EAT) when I bought it. It wasn't much, maybe 5 seconds or so, and only after sitting for at least a couple of hours. That was when I bought it 3 years ago. I had a transmission flush done on it, then it went to 10-20 seconds after that. It wasn't a showstopper, so I've lived with it for a couple of years now, planning on having the transmission dropped and looked at when I got my tax refund. That never happened as there was always something more immediate that ate the money.
I put a $10 can of Sea Foam transmission additive in it a week ago, and the problem stopped! I followed the can's instructions plus what the partscounter guy said as well. I ran it thru every gear for at least 5 minutes... including reverse. I probably got some funny looks as I was making full-lock circles in reverse for 5 minutes in the school district's parking lot.....
I'm happy! I wish I'd done this 3 years ago. I suspect that the problem was just a sticky valve in the valve body all along, and a thin solvent-type additive was what was needed to break it loose.
The Sea Foam brand of additives isn't usually found in your usual Shucks/Autozone/etc store, it's more likely found in more "shop oriented" parts stores like NAPA.
As with other cheap fixes, Your Mileage May Vary. (YMMV)