new trans mounts - too stiff?

[JayB]

1960 Corvair 569 3 speed manual.
Got new trans mounts from CC to replace originals which were dry, shrunk and cracking a bit. Easy install with power train out.
But it is now NOISIER with MORE vibration when Idling. I thought they would IMPROVE the dampening effect...but apparently, the opposite?

I did not fully torque the castle nuts to the 60/80 as manual said, but probably 40-ish.

Has anyone experienced this? Does greater tightening reduce vibration transfer? Or did they manufacture these with harder durometer rubber than original.

Thanks, again.

[64powerglide]

Got mine from Clark's & don't have any noise, maybe they are to loose.

[clarks@corvair.com]

The durometer was matched to all the GM NOS mounts, specific detail was put into matching the durometer with the originals. As with all of our reproduction parts it takes a lot of research and testing to make sure each reproduction piece ends up as close as possible to the originals and whenever possible we make improvements to the reproduction part over what GM made.

Clarks Corvair Parts

[JayB]

No more problem with the mounts. I torqued them to spec. 70 # and all is well. I also read in the manual that if under-torqued can put energy into into other components causing other problems as well. All that excess vibration is gone. Thanks for the advice. It helped to solve the problem!