great write up! From the return line , can i run that to a external trans cooler and then back to the return line , or should i bypass the rad cooler all together?

I'd run both coolers...

Run both unless you've had the trans rebuilt and the rebuilder disconnected it. That usually means they didn't replace the cooler and there could be debris from a previous meltdown in there.

thanks for the speedy response on that , sorry squirrels for thread jacking for a second..... tranny hasnt been rebuilt , but it is a new rad so its pretty clean in there , unless theres stuff in it now.

no problem, this thread had died anyway. It's in the DIY section for posterity.

A couple of observations and questions for those that have done this. I had that union apart today to complete a tranny fluid swap. The line with the check valve wasn't a return line, it supplied fluid to the cooler. Reason I know this is because I was set up to catch the fluid from the check valve side in a gallon jug but when I started it up fluid pours out of the rigid side(metal). Oh well after I recovered from this mishap I completed the fluid swap.

I was looking closer at that check valve and wondered why I couldn't just drill it out instead of fiddling with all those fittings. I might do this but wanted to get some input before I jump in.

You might be able to drill it out, but I would be concerned with debris from drilling being left behind and going into the tranny, or cracking the check valve housing and having a catastrophic failure at a later time.

Copper is a soft metal, cracking really not a concern. I could easily blow it clean with an air compressor. Really the input I'm looking for is long term,that is....I'm torn between just cracking open the union from time to time to check for a buildup or doing a mod.

Nice write up OP I've been having tranny problems that seems like flow restriction to me, seems this is the 1st thing to check into.

Small update to make obtaining these NAPA parts easier for the next guy who tries.

* Part # for quick connect is #730-5027, not #730-5927. This one really threw the guy for a loop.
Strange, as the pic seems to clearly show 5927, must have changed it since the OP, as a part number search at NAPA will verify
http://www.napaonline.com/NOLPPSE/(S...)/Welcome.aspx

* Part #'s for the 2 3/8" nozzles & 3/8 to 1/4 reducer are good, but switched around.
So you will need 2 05706B106 and 1 3300X6X4