rear end clunk spicer 80

[melmount]

I was fixing my truck all day today. I decided to listen for the rear driveline clunk. I had my wife get in and go from reverse to drive and back etc etc.
It really sounds like its coming from the rear end, right around the yoke. I was totally under it while she was doing this, its not the tranny area.
It also seems to sometimes clunk when i am about to come to a stop.
I have greased the slip joint and real confident its not that. U joints are newand a new carrier bearing. I have no whine going down the road. I dont have a dial indicator, is there a way i can eterming if its either ring an pinion or the bearing for it? I used a pry bar and it does not appear to have up and down play(yoke)

[66Bronco]

Sounds like axle wrap to me. Ladder bars will get rid of that. There's a write-up on here about doing them with top end links.

[melmount]

whats axle wrap? can you explain? This is my 3rd dana 80 rear. One was wsted, the other in my wifes dually. Hers clunks into gear too. I think its the rear. I am starting to think that since theres no crush sleeve, its shimmed to a spec. That thats not completely tight. Allowing for a clunk???
Whats axle wrap? How could it be from idling and going rev to drive and back? Its not a clunk under power over bumps or 4 wheelin?

[melmount]

you guys that take these apart, think its clunky due to the use of spacers wrather then crush sleeves?

[66Bronco]

Axle wrap is caused by the torque about the axle that the rotation of the driveshaft causes while turning. And yes, it can happen from a stop, as you have an automatic transmission, so the rear driveshaft is effectively always engaged. just imagine the rear axle as a pivot point and this causes the pinion to rotate up when in reverse and down when in drive. Thus the clunk you hear is the tangs on the yoke. Depending upon how many miles are on your truck, this is partially due to the springs softening over time. Ford uses the rear leafs to locate the axle and control the wrap from the factory, and as the springs fatigue, the effects of axle wrap become more marked with age. I hope this clears up any confusion.

[melmount]

whats this mean "Thus the clunk you hear is the tangs on the yoke"
I understand the force of the shaft. I get the pinion yoke being forced up and down depending on whether in forward or reverse. But exactly what is the noise from? what two parts hitting? I was thinking ring and pinion area?

[66Bronco]

By tangs, I mean the ears on the yoke.

[melmount]

whats hitting what? this noise i hear is something hitting something?I was under it last nite and my wife shifted it back and forth. It was the rear end, somewhere? I dont doubt its the pinion, but itsnot hitting the flooror anything.

[66Bronco]

The yoke on the pinion side is contacting the yoke on the driveshaft. If it is in fact axle wrap, it will occur under hard acceleration also. It's not really a big deal, so long as it's not excessive. If it is, and you're running a lot of power, you run the risk of snapping the pinion shaft. But like I said, ladder/traction bars will mitigate, if not eliminate it altogether.