First the disclaimer... I don't really know Isuzus.

Bank 1 & 2 refers to V engines where each side has it's own primary O2 sensor. 'Primary' & 'secondary' refers to before vs. after the catalytic converter. If the SLX has only one primary O2 sensor after the exhaust connects together into 1 pipe, then the OBD-2 error codes still(!) call it bank 1. If each side has it's own O2 sensor, then I don't know which side is which. There's different codes for misfires on any particular cylinder, that's different than 'lean on bank 1'.

Typically automatic trannys drain from a drain bolt on the bottom & fill thru the dipstick tube. Is the automatic tranny behaving bad, or are you just changing fluid by the maintenance schedule? 'Real' Honda automatic trannys don't have a normal replacable filter/screen like most other. But Isuzu??? If it has a pan on the bottom of the tranny then maybe it has a filter?