They should both be Isuzu Corporate 12 Bolt axles with disc brakes. I don't remember off hand which year went to a slightly wider axle, but I'm thinking it was later than '96.

What exactly did you grenade? Potentially, you might be able to pull just the third member and replace that, rather than the entire axle, and that should be the same from one to the other, barring a possible LSD question.

James