MrTracy

Had a vibration in the rear end at 2K when in high gear (5+). The vibration lasted for a few seconds until the rpms went up 100 rpms or so. I thought it was the trans mount. I changed the trans & engine mounts. The vibration was still there. It was so bad it vibrated the rear deck. It was however less than before the mounts were changed but not by much.
I dropped it off for the mechanic to look into it further. I also informed him to install a new high capacity trans pan 7 the rest of associated transmission bits. My mechanic also informed me I had a small leak in my diff. He said he didn't have time to fix the diff put he topped it off. I am to dropp off the car for the diff work next week.
Anyway, when I picked up the car the vibration was gone.

Any thoughts?