Hi I'm Wayne, I will help you with this,
It is filled with Dextron ATF. JCB does say not to use Dextron due to some of the seal problems that they have had with the convertor and front pump. Dextron will work just fine.
In the transmission box, the second housing past the converter, is 90 wt gear lube. This is just a simple gear transmission and is separated from the shuttle.
if this helped you, please hit Accept......if not get back to me
if you want to use NAPA oil, they will cross it over from the Dextron ATF