How does tranny fluid get pumped through radiator?

Sorry for the dumb question, but what pumps the tranny fluid through the radiator for cooling? I just changed my radiator, and now my tranny is acting up. I did a fluid and filter change, but also want to make sure the fluid is getting cooled properly.

there is a pump in the front of the trans thats driven by the torque converter. It supplies the fluid pressure for the trans to work and pushes the fluid through the lines to the radiator cooler.

Hopefully you searced and read enough before to know that DexIII is the required fluid and many people have posted bad results using anything else. When you changed the radiator, you must have hooked the tranny cooler the same as it was before. Did the cooler come with plugs that had to be removed?

On that note, I see that MD3 has pretty much replaced Dexron III. Thought I'd heard of some folks having problems with the switch, something about MD3 has higher detergent properties and was scouring the years-old sediment in the tranny and clogging lines/filters with it. Anyone have any info on this? I haven't seen Dexron III on the shelves for awhile and need to service my tranny soon. Is Dex III still available? I'd rather not put in a fluid that has been problematic, regardless if the manufacturers tell me it's safe or not.

And if you need the route of the lines, you can find the diagram in here:



http://www.naxja.org/forum/showthread.php?t=951283&highlight=mixed+tranny+lines

'92 XJ