I've got a 92 z28 and I'm fixin to install a transmission cooler. Can anybody tell me which line is the return line, the TOP or BOTTOM?

 

I couldn't find it in Chilton's so I am not sure. However, should it matter? Both lines come into the radiator so you will disconnect both and insert both into the cooler, right?

 

If he wants to run an external cooler in addition to the internal cooler, no.

I can't tell you which is which, but I can tell you that the pressure drop across a tranny cooler is negligible, so you don't have to worry about the feed line having too much pressure for the rubber hoses (unlike a power steering cooler.) Putting it on the return side will cool the fluid slightly better though...if you're ambitious you can unhook the lines and have someone turn the engine over a couple times. The one that squirts is the feed line.

 

im pretty sure it the bottom!