I suspect they get installed all which way at the transmission, either at the factory or when serviced by the Dealer. When not sure, an inline filter on the return line would be prudent.

A radiator shop may have the diagrams. Can't seem to find them on the web.

The counter flow heat exchanger is more efficient per EngineersEdge at http://www.engineersedge.com/heat_ex...nger_types.htm and this web site:
http://www.wisegeek.com/what-is-a-heat-exchanger.htm
"There are three primary flow arrangements with heat exchangers: counter-flow, parallel-flow, and cross-flow. In the counter-flow heat exchanger, the fluids enter the exchanger from opposite sides. This is the most efficient design because it transfers the greatest amount of heat. In the parallel-flow heat exchanger, the fluids come in from the same end and move parallel to each other as they flow to the other side. The cross-flow heat exchanger moves the fluids in a perpendicular fashion."

 

i'm pritty shur that teh fluid goes from the trans to the bottom out the top and bakc to the trans at least thats the way i findem and put them back the same way. my local trans guy says thats the way theys spose to be. he said so if you have junk in there it'd plug the cooler if the fluid flowed top down buy flowing bottom up junk would more likely float around and not accumulate at the bottom from gravity. sems to make allot of sence

 

Flow up is the way it's suppose to be. More efficient cooling (counter flow) plus likely less dirt getting into the system, as you say.

Wonder how many times the the transmission flush guys get them hooked up backward at the transmission. Oh well, putting dirt in the transmission may get the Customer back for repair work.

 

so then why do all master mech say the other way? i dont get how come so many people say to do it backwards

 

My guess is that it doesn't make much difference unless there's an external cooler involved, if which case, it is hooked up right to maximize the cooling efficiency.

Then again I had a Mechanic at a Dealership tell me the rear cooler line at the transmission was the return. Not all Mechanics are what they seem to be. What do you think of this answer at this site?
http://www.justanswer.com/questions/...an-3-0-4-speed