[HEQT]

Here is a wierd one. My Dad built a
33 passenger Bus chassis into a hi-
speed motorhome (he's a leadfoot).
He did this by removing the center
bearing between the front+rear drive-
shafts and installing a second trans
with a 40% overdrive in hi range. The
drive shafts were modified to fit by
"pros". We used this Bus for years,
but it always vibrated from 40 to 73
MPH. Above 73 and up to about 105 MPH
there was no vibration at all ! So,
he always drove above 73 MPH ! Suddenly , the situation changed.Now , the vibration builds up and the rear
(40% overdriven) driveshaft explodes
into pieces the size of a quarter. He
has had this happen 3 times in a row...Obviously something else is wrong and he will not go to a professional truck mechanic due to
retirement "poverty"... I would like
to get this "road warrier " Bus back
on the road as it was fun and unique .
Does anyone have any ideas to fix it ????? Thanks,

[Bent Wrench]

Is it at all possible that the differential may have rotated slightly on the perches? Sounds like a change in the "angle of attack" by the driveshaft. May not be the problem, but would be interested to know what you find out that cures the problem. Good luck!

[KULTULZ]

Did he originally have enough space left after installing the auxiliary trans to retain the center carrier bearing? It does sound like pinion angle, and possibly the main shaft being too long in length.

-Pinion Angle Theory-