[sidewaysalfa]

But, with this thread I already know what the problem was. And fixed it.

Here were the symptoms.

Recently the drive line was giving problems.

1. Bad rattle at idle, and between shifts. Sounded like something was hitting the hollow driveshaft: bang, bang, bang, . . . the noise was definately coming from the center bearing area.
2. Massive vibration at and above 3,800rpm. The shifter wanted to vibrate right out of the car.

We put the car on a lift and inspected the donuts. All in good shape.
At that time it appeared the only thing was to pull the whole thing out.

Any opinions? The answer, later.

 

[AR4me]

One or both 13mm nuts for the center support had come loose?
Jes

 

[fetta78]

Snake in the bellhousing?

.

 

[sidewaysalfa]

Well Jes is completely correct about the bang, bang noise. Vibration was something else.
But Mark gets high marks for creativity.

The 2 nuts were about completely backed out. (The guy who changed the center support bearing (me) about 1,000 miles ago seemed to forget to put LockTite on the threads!!. I guess that made the yoke that the nuts hold in place, slide back and forth on its splines, banging into the driveshaft.
The vibration was that 1 of the 3 nuts holding the center donut was just a little loose, not much about 3/4 turn from tight (see the above note about "that guy"). I corrected the loose nut problem and that solved about 95% of the vibration.
Correcting the yoke nut problem seemed to almost eliminate any driveline vibration. Thou there is a little above 5,500 rpm.
obtw: The 2 nuts, 30mm socket, fit into a tight hole in that yoke. A hole that is just a little bigger than the socket I got from Kragen/PepBoys. Poor casting flashing was removed with my Dremel rotary grinder and the socket fits just fine.
obtw2: The center support bearing was from a later model Alfetta and the support bolt holes are a little to close together. A little work with a file changed the holes to slots and it fits just fine on the 76-77 chasis.

 

[gt601]

I had mine do the same thing but the only warning I got was a little bit of vibration and the drive shaft was pinging the shifter once in a while. I thought the shifter had a problem until the last nut fell off and all hell broke loose under the car. I still put it on the rack and check them at least once a week.
Oh... I didn't mention that the looseness was my fault.

Paul