Is there any way to isolate whether the issue is with the viscous coupler / center diff vs the front differential? Car shows classic signs of center diff failure, but mechanic says he "feels it all in the front, so it must be front diff" and therefore needs a new transmission. I can't afford to throw money at this and a tranny is out of the question.
Car has no symptoms cold, but locked 4wd when warm, noticeable when parking, and worse after highway.