What's broke?

Dexron isn't 'made for' stick transmissions. The folks selling the New Process gearboxes in their cars (Mopar) say it is suitable for use in those gearboxes. No argument is being made that Dexron is The Best oil for the job, but it cannot be argued that it is NOT suitable for use.

Ha...well, of course it can, but it is neither a useful nor correct argument.
I'll be Honest, the NP 3500, bowtie used it also, I had a Dakota that was pretty quick, a 5 speed 3:92 rear end, with that transmission they are almost unservicable pieces of garbage... please don't take this as an attack on you, or your knowledge, or anything like that. Just me and that particular transmission are not friends,, and never will be again, hopefully they are using something better, it was an 01, with single cab, short bed.