Well its better to plan where you turn around if you otherwise are confident enoguh to use it on the road. Like a small incline and a wide open area and be ready to let gravity pull you moving then use the wheel to turn and once you have enough turn around go forward. but thats basically a country road with visibility and an elevated shoulder thats wide and hoping that isnt the only issue to deal with lol.
is it an unrestored original build you think? Is the fluid you using just universal dex/merc or maybe a type F? it may sound stupidly dumb/simple but I managed to fix E4OD issues on f150 (albeit overheating and puking fluid) with unscrewing the top(easiest to reach) cooler line and using a can of compressed air and shooting a little up the line and letting it yank a little fluid out and then a little burst at the cooler
I forget which direction it flows the lines but I cranked the truck and pushed fluid out of the cooler and some dribbled back out the line. The cooler was too restricted.
and final bit that may be worth a thought is the dipstick original and is it a later 80s? 90s? I cant remember if I rear about the incorrect dipstick length in ford tsb or GM but making sure its the right level I guess you never know.
-those old coolers for years game gm issues because the slightest debris or restriction would kill remans or warranty replacements especially if there had been catastrophic failure. So much so they required flow testing and flushing them whenever there was a big service. and the cooler in that radiator may be has some hard deposits inside. The oxidation test between dex iii and dex vi was night and day and the TH400 is from the days of DEX I and II, which had organic additives. dex ii turned unslightly shortly after being in the trans and that could possibly make seeing what condition it was in and maybe was left too long etc.
I hope its not too bad tho
