Triumph Repair: 1973 TR6 rear end noise?, www youtube, ring and pinion

Question
I have included a link to a video on Youtube, you can head the noise when I coast and while driving not sure where the noise is coming from my brother said maybe the ring and ping? below is the link

http://www.youtube.com/user/rocketvdo?feature=mhw4#p/a/u/0/e2XgMMxNdX0

my user  link is..

http://www.youtube/rocketvdo

any help would be deeply appreciated
Thank you
Ron

Answer
I worked in several Brit car dealerships for many years and I never was able to just listen to a noise and tell you what it was. THE ONLY WAY I COULD EVER FIND A NOISE WAS TO RUN THE TESTS I TOLD YOU TO RUN. The ring and pinion is just one of many possible causes so run the tests I told you to run and you will then know what is the cause.
Howard

Opps! second answer. Sorry Ron, I thought I just answered this question. But I think it was someone else with the rear end noise.

Anyway, the only way I could ever diagnose a rear end noise was to put the car on a lift and use a mechanics stethoscope to listen while the car was in gear and running at the speed and in the gear that it was most noticeable on the road. A mechanics stethoscope is not expensive and will get used many times if you plan to keep a car. An old mechanics trick before stethoscopes was to put a large screwdriver up against what ever you wanted to listen to and the handle tight against your ear.
Too many mechanics make major repairs on cars by guessing what a sound is. I just had to do this test on my own XJ-6 yesterday as I heard a noise that sounded like a wheel bearing in the right rear of the car. Jacking the car up and setting the speed in gear I used my stethoscope and found that the LEFT rear wheel bearing was bad. So noise can radiate through the car and sound like it is coming from a different place.
If you do have a pinion bearing bad, you will need a service manual as the replacement of a ring and pinion is a large job even for an experienced mechanic.

Howard