I just got a '95 Honda Passport 4 x 4  w/3.2ltr motor. The LF hub sounds like it's trying to engage every once in awile. It makes one helluva racket for a few seconds and then stops. I pulled the hub & found some definite wear on the ring gears. I cleaned, R & R'd the seal & inside bearing and put it back together. Any ideas on the culprit??  

The Haynes manual sez there's a "vacuum shift motor" which appears from the pic to be mounted at the front axle - but there isn't any on this car - or I'm blind in one eye and can't see put the other. It's been awhile since owning a 4 x 4.

Regards,

Brooks