Noise in off circumstances. Can't find source.

[97blueyuk]

Title should say odd circumstances

97 Yukon. The other day after driving about 5-7 miles I stopped for gas n coffee. I left the store and about a mile down the road I started to hear a clunking sound only above 20 mph and only when pressing accelerator. I stopped and checked the driveshafts and u joints no problems. I got it home.

I put the rear in the air and put it in gear and heard the noise. Checked the rear diff, was a little low. I filled it. Still have noise. Brakes look ok. Very little play when shaking the rear tires up and down and side to side.

Anyone have an idea what this could be?

It only does it on acceleration above 20 mph. If I get to about 40 and coast it goes away or is so slight I can barely hear it.

 

[97blueyuk]

On pass rear there is a cracked brake shoes ( the rear one). Again, minimal play up and down and side to side.

 

[bunchz71]

Could be a broken transmission mount. Under acceleration, it would cause it to jump up and hit under carriage. I would start there.