np208 loud grinding noise/hot tailshaft

[496truck]

Sometimes. When GM built the shafts originally they pressed end yokes into the tube and then welded. What I was told over the years by several driveshaft shops I've dealt with is that the yokes can't be reused cause they don't have a way to press them into the tube like GM did.

So, now why can't they cut off the front end and use a new yoke and CV leaving the tube and rear yoke intact? In many cases the original tube is thin from rust and brittle and easy to break, plus it's thin walled anyways... so I've been told.

And, really, what are you saving by reusing the old tube? $20? $40? $50? That's a small price to pay for a whole new unit with a thicker wall tube, new yokes and joints, balanced and guaranteed for workmanship.

Just something to think about...

 

[CherryK5]

Sometimes. When GM built the shafts originally they pressed end yokes into the tube and then welded. What I was told over the years by several driveshaft shops I've dealt with is that the yokes can't be reused cause they don't have a way to press them into the tube like GM did.

So, now why can't they cut off the front end and use a new yoke and CV leaving the tube and rear yoke intact? In many cases the original tube is thin from rust and brittle and easy to break, plus it's thin walled anyways... so I've been told.

And, really, what are you saving by reusing the old tube? $20? $40? $50? That's a small price to pay for a whole new unit with a thicker wall tube, new yokes and joints, balanced and guaranteed for workmanship.

Just something to think about...

That's true..
I guess i'll shim it and drop it down an inch or so and then save for the new driveshaft.

Although when I do the 5.3/4l80e/208 i'll need a new one anyways.. I might band aid it until then.

 

[Blue85]

Are you sure the upper yoke isn't actually hitting? You've added a lot of angle to it. Vibration is definitely expected with the big angle mismatch. Do you have any lift blocks or is it just stock rear springs with the shackle flip? Was the rear end really binding with the driveshaft removed?

I was in the same situation for a while and just used shims to point the pinion down, plus a 1.2" T-case drop. I ended up with about 13 degrees in the joints. It did vibrate some on the highway, but I was able to live with it for a couple of years. It's pretty hard on the slip yoke though.

 

[CherryK5]

Are you sure the upper yoke isn't actually hitting? You've added a lot of angle to it. Vibration is definitely expected with the big angle mismatch. Do you have any lift blocks or is it just stock rear springs with the shackle flip? Was the rear end really binding with the driveshaft removed?

I was in the same situation for a while and just used shims to point the pinion down, plus a 1.2" T-case drop. I ended up with about 13 degrees in the joints. It did vibrate some on the highway, but I was able to live with it for a couple of years. It's pretty hard on the slip yoke though.

The yoke clears with about a sixteenth of an inch at fool droop.

Im going to drop the tcase an inch, pull the add-a-leaf, and install shims. Hopefully that fixes it for a while.