Unfortunately, I haven't installed mine yet. Summer sort of slipped away...
I'd check with Matt(Indy 4 X) via phone call before getting a setup third with 5:38's...Unless he's been able to get some 5:38's made for the rear 12, you'll have a hard time (if at all) finding matching ratio rear gearing.
IIRC, the only Isuzus that could use 5:38's, were the ones that came with Dana 44's...check it out, I hope I'm wrong.![]()