Vehicle: 2006 Toyota Tundra -SR5 - 4wd - 227,000 miles - 4.7 V8

***I know next to nothing about vehicles besides how to change a tire and the oil. So bear with me. Any response is appreciated.

Problem: The last 2 years I've had a vibration coming from the read end at slow speeds, especially going uphill. I took the vehicle in twice to the dealership and to a local mechanic shop, to no avail. I occasionally have a popping or clanking sound coming from the rear but it's usually the vibration/rallting sound. Finally took it to a different mechanic and he called me back instantly to say that my rubber bearing on my drive shaft was worn out and needed to be replaced. So $250.00 later and i'm back on the road. Oddly, the issue seemed ok for a couple of days and now it's back to doing basically the same thing. It seems to be a little better going up hill but turning at slow speeds and backing up is still causing a clanking and vibrating sound. I have had axle leaks in the past but those have been fixed. Any suggetions on what the issue could be? Thanks!!!!