I beg to differ
my 76 727 short shaft is the same thing,manual shift it,it works and goes...pull up to a stop and forget to down shift it..no pulling off in drive...just crunching/grinding sounds till manual shifted to low
drive it like I stole it,manual shifting with on/off the gas and no coasting or auto shifting.you could not tell it was toast,never sliped or missed a gear,it still worked by manual till I pulled it..deff the sprag..I had rollers in the pan
mine came about from about 15-4800 rpm N drops doing hole shots with it
i still have it in the shed,best 50$ tranz I have ever bought..lasted for 10 yrs till that night
its too bad,but I think its a good move with that truck repair,IMHO
a used JY tranz may be fine and may not and a rebuild is $$$ to have it done right
good luck on ebay/CL