2 Years ago I had to replace by driveshaft assembly because the rubber bushing holding the center carrier bearing weakened causing severe vibrations. When that started to fail on me it only took a hundred miles or so from first vibration to thinking your transmission is bad. Lucky it was "only" the $500 driveshaft. It was better after replacement but still had a faint vibration if you floored it. I read elsewhere in this forum of some poor guy having to replace his driveshaft 2 years after doing a new one. Turned out for him it was the transmission mount as a possible root cause. Due to age it became softer, flexing more than designed, forcing the center carrier driveshaft bushing to flex more than designed.
Mine looked OK but was actually sagging. Look how the center castle bushing is no longer flush with crossmember.
The new mount has stiff rubber while the old one looks perfect but can be twisted a bit just by hand. Replacement is not hard and the part costs less than half tank of gas. No more vibration while stomping it. I do not want to buy a $500 driveshaft because of a $15 trans mount.
The after shows the castle bushing flush with crossmember. It's bolt thread depth is limited and the nut only screws on so far.
Mine looked OK but was actually sagging. Look how the center castle bushing is no longer flush with crossmember.

The new mount has stiff rubber while the old one looks perfect but can be twisted a bit just by hand. Replacement is not hard and the part costs less than half tank of gas. No more vibration while stomping it. I do not want to buy a $500 driveshaft because of a $15 trans mount.
The after shows the castle bushing flush with crossmember. It's bolt thread depth is limited and the nut only screws on so far.

