[reptillikus]

While you have it a part install a punisher valve body

Consider upgrading the line size and cooler size (over oem). That's where the e4od is lacking compared to the newer transmissions that last longer because of better cooling. Seattle FSB has a line upgrade write up.

Definitely install Punisher valve body.

You dont necessarily need to upgrade the cooler hose size, but i do recommend the biggest cooler you can fit. If you had a built motor along with a fully built trans then id consider upping the cooler line size. The big trans cooler Ford offered in the later model (94-97) pickups is massive and does a great job keeping the E4OD cool. And you can get them cheaper than an aftermarket cooler.