Just bought a truck from a dealer had a vibration at high speeds. Went back and narrowed it down to a weight missing from the middle of driveshaft. Replaced with used driveshaft and vibration was gone. Now it is leaking where the driveshaft goes into the transfercase. If you push up on the driveshaft as if to check the universal joint i hear a clumcking in transfercase. Could it be seal and bearing are shot or could there be more damage in transfercase due to virbation from bad driveshaft?