Exhaust, Tranny or Rear End noise?

[MPGmustang]

I've been driving my car for 3 years now, but I don't think I remember the hum until I did the engine/exhaust about 6 months ago... well I can't remember what it sounded like back then...

so I've been thinking that I have an exhaust drone/hum at high speeds. and my conclusion is that it was the exhaust, but recently some one told me that it could be the rear end pumpkin... granted it 47 yrs old and coded correct for the car. but how can I test to tell where it's coming from.

I wanna test if it's the tranny or rear pumpkin or exhaust that i'm getting the drone/hum from.

how?

 

[bubba22349]

Grab the rears yoke and turn it back and forth (wheels on the ground or blocked from moving) there should not be much play.

 

[MPGmustang]

from the looks of it seems to move ~1/4 inch, i'll get a tape measure to comfirm

 

[CobraSix]

Sounds like your rear end is starting to finally go. Or, possibly an axle bearing.

With the power you are at now, with a 47 year old rear end, it's likely at the end. Exhaust drone is usually noticable.

A couple of quick tests.

Drive down the road, get up to a good speed (35-45) and clutch out and let the engine idle. If you still hear the noice (at the same frequency) it's likely an axle bearing.

Next, put it back into gear. Give it gas for 1 sec, off for 1 sec. If you hear clunking, usually it's the u Joint. Or, Bubba's method is less destructive.

If you back up in reverse, is it getting louder then before? If so, likely the rear end is going bad. For some reason (well, it's gearing) reverse is usually the indicator for rear end wear.