My 80 is vibrating a lot when getting at highway speeds. This happened after I had the front axle seal replaced (the one on the differential not the pinion). Before I got it to my normal shop I had it taken to a gas station to get it filled with gear oil to get it up to the shop. Well, what they did is take off the paper seal around the diff when they put oil into it. Now they did this without asking or without me knowing. My question is when the third member was bolted back on without the paper seal could that have moved the transfer case making the driveshaft not straight and cause the vibrations?