do you have the stock chain tensioner?
tossed mine in the trash it was ratcheting up the chain way too tight so that being said i went with the baker manual adjuster
I have heard about crank bearings and trannys input shaft bearings turning to toast
once the bearings start to get torn up and they get some play the automatic tensioner just keeps on ratcheting up the tension its a vicious cycle until there is a total chernobyl melt down I would open the primary just to be sure better safe than sorry
I don't care what magic oil you run there will always be something on the drain plug (I run Mobil 1 atf synthetic)
Yours does not fall into the OH Crap now what category in my opinion
Its called deterioration resulting from ordinary use and exposure to heat
I have rebuild dozens of gear boxes, differentials, transfer cases,manual and automatic transmissions
if things are good button it up ride it like you stole it....