Fwd: <VV> Jacking

[HallGrenn at aol.com]

In a message dated 8/27/2006 1:55:32 P.M. Eastern Standard Time,  
hyarnell1 at earthlink.net writes:

I have  always put a roll jack under the differential, but have been severely 
 
chaistized that I'm ruining the motor/trans mounts. Can't see why. You'd  be 
putting the mounts (all three) in compression. They already are in  
compression with the car just sitting there. Can someone explain to me why  
this is wrong?

Harry Yarnell



Harry,  One of the main reasons I have not jacked my cars using the  drive 
train as the jacking point is that you are lifting something that is much  
heavier (the car) than the drive train the three mounts are supposed to  
support--in the opposite direction from which they are supposed to work.   On a fairly 
new car or with new remanufactured mounts you may get away with it  for awhile, 
but eventually the reverse shear will be detrimental.
 
P.S.  In an earlier post I recommended using the skid plate to support  the 
engine when changing a rear mount or the harmonic balancer.  I anyone  took my 
message to mean jacking the engine/car with the skid plate please  don't.  You 
can support the engine by the skid plate when you want to take  off the rear 
mount, but don't jack the rear with it--good engine mounts are  getting more 
and more expensive.
 
Bob Hall
Group Corvair
'64 Brier
'65 Corsa
2 '68 Monzas