Good afternoon

I own a 1993 Ford Econoline with 156000 miles. It is the extended version. It has a 6 cylinder engine. I have only owned it since the beginning of the year.
Recently I noticed a clunking sound when I let off the gas, usually at lower speeds. I am having a hard time distinguishing where the sound comes from, but i think its coming from the rear of the vehicle. Also the whole vehicle seems to rattle when I go above 50 (and sometimes at lower speeds). I have avoided driving over 50 because of this.
I read on a forum somewhere that I should check the u joints for cracks, which I did and found nothing.
I have taken several photos of the underside of the vehicle and can email them if it will help.
I would like to take this van out on the road for five months, but I am not sure it is safe to do so...
All help will be greatly appreciated.

 

The u joints could be causing the clunk and if they have never been replaced and you are going to be on the road for that long , it would be a good PM measure to have them replaced. The mileage kinda says so !