Donut, doubt

["Lee Scanlan" <Lee.Scanlan@domain.elided>]

I am re-sending the following, didn't see it appear earlier, apologies for
any duplication. Lee.
                             ------------------------------
I have recently replaced the rear donut on my Alfetta sedan after a complete
segment flew off and the remaining item broke up with a big bang and
discernable vibration.

Whilst fitting the new donut, obtained overnight from helpful Turin Imports
of Adelaide, I noticed the rubber  moving through a good bit of axial
ditortion as the six fasteners were tightened. After all the nuts were tight
the donut looked like a giant rubber wave washer, it's as though the rear
end of the rear shaft was too far away from the gearbox/clutch input spider
(three legged spider) and the rubber was being "pulled" to meet both faces.
This helped to explain why the old one broke. Is this normal? The distortion
could be a result of some angular displacement, on the vertical plane,
between shaft and gearbox, very obvious on the bottom most segment, the part
you can best see, gearbox mountings are good so I don't believe the
transzxle is nose down.

I can't help but think this isn't the way it was meant to be, the coupling
must be constantly changing shape, the other two aren't subject to this
torture and is possibly why they have no cracks despite being the same age.
In AD7/1078 Mike Grace researching a 105 driveline vibration mentioned
receiving advise to shim the donut fasteners to relieve any tension in the
rubber, if it were NOT an angled alignment problem this might work. Car runs
fine but I'm wondering for how long. Does the rear donut normally fail
soonest, can anyone offer any advise or comments please?

Lee Scanlan
Perth W.Australia

------------------------------