I have been having a hard time to get a road race transmission oil cooler 12 volt pump that lasts. The purpose of this pump is to suck oil out of the tailshaft housing, move it thru an aluminum cooler, and then return it to the front of the transmission. I have tried a Jabsco Water Puppy pump, but the vanes keep breaking off the rotor. The standard pump rotor appears to be made of Buna, and they have an optional rotor that is Viton (more oil resistant.) Both of them will break off the star points of the rotor with less than an hour of operation. This pump appears to have way to large of a flowrate for what I think is appropriate to circulate transmission oil.

I next tried a Holley red fuel pump. This pump has 4 flat metal vanes that ride in grooves in a rotor. It worked for awhile, but I think the thick oil eventually made the vanes stick in; the pump couldn't spin fast enough in the thick oil for centrifugal force to keep the vanes slung out against the pump wall.

What brand do you have good experience with?

 

I know some who use these:

http://www.racerpartswholesale.com/mocal1.htm

If you'd like a lower flow rate add restrictors to the line.

 

That looks nice, and the flow rate is reasonable too.