First off, if you clamped the mount down in the vice with more
force than the front of the motor will put on it, you could
easily compress it till the plate hit the retainer. The front
of the motor with the trans cantilevered off the back will only
put a few hundred lbs. on the mount. It does not compress all
the way down like you're doing in the vice.
And again, when you install it, don't tighten the bolts that are
in the front plate down tight, just snug them up and put the
castle nut. Only the bolts that hold the mount down to the
frame are torqued down tight.
And if you lift the front of the motor you should be able to
remove the mount. I'm made a wood saddle that supports the
engine at the pan and using a jack lifted the front of the
engine enough to replace the front motor mount. My truck is
a 3600 and does not have a mount on the back of the transmission,
you might not be able to do this with a 3100 with the rear motor
mounts still bolted solidly in place.
Denny Graham
Sandwich, IL
