Trans mount - MikeL/Evan preferred?

oscyjack

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May 7, 2016
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I'm in the process of setting up a time with Evan for my trans build at the end of the summer/beginning of fall. I've been getting some really insane vibrations that I couldn't track down. Realized yesterday that my trans mount is allowing movement in all directions when I used the output shaft to move myself under the truck. So, I bought a poly mount from merchant, just curious if I made the right choice or if builders have a preference for another part. thanks
 

CarolinaHD

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Feb 8, 2011
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From what I was told you need to have merchant automotive style engine mounts as well. The trans mount will be too rigid and the motor mounts will be too loose causing something to break.
 

rennat_2006

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Feb 18, 2010
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Thats correct, youll probably break the case running a stiffer/harder trans mount than motor mounts. Run poly motor mounts and a poly trans mount is fine, poly motor mounts with a stock rubber trans mount is fine also.
 

oscyjack

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May 7, 2016
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Thanks boys. Should have looked before I leaped, hopefully Merchant hasn't shipped out yet and I can swap the order.
 

oscyjack

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Thats what it is then :). I had read lots of back and forth as to whether or not the poly is good, or works with regular engine mounts etc. Since Evan is going to do the trans when the time comes, I figured I should ask him and Mike what their preference is since they deal with these every day, and i'm a first timer.
 

c20elephant

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From what I was told you need to have merchant automotive style engine mounts as well. The trans mount will be too rigid and the motor mounts will be too loose causing something to break.

I have Merchant engine and Energy transmission mounts in mine, this was my thinking on it also, but I can't say if I have ever read about it.

The stock Allison transmission mount (nothing special about it and was used way before the Duramax/Allison combination)) looks like an afterthought from GM as it is used on many other applications (read the comments at the bottom of the link) like a S10 trailblazer and many more.....

http://www.energysuspensionparts.com/3.1129
 
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Mike L.

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Aug 12, 2006
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I have Merchant engine and Energy transmission mounts in mine, this was my thinking on it also, but I can't say if I have ever read about it.

The stock Allison transmission mount (nothing special about it) looks like an afterthought from GM as it is used on many other applications (read the comments at the bottom of the link) like a S10 trailblazer and many more.....

http://www.energysuspensionparts.com/3.1129

Reading the article is like discussing hen house security with the fox.:roflmao:
 

Leadfoot

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Dec 27, 2006
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While not a true apples to apples comparison, its basic principles are the same.

Years ago after doing a restoration on my 80 K20 (with new factory motor and t-case mounts), I went truck pulling. I noticed my transfer case shifter moving quite a bit (old school through the floor shifter) in the cab under torque. I decided I needed to stiffen it up and bought Energy Suspension polyeurethane mounts for the transfer case. The very next pull I broke the adapter between the transmission and transfer case (expensive mistake). After that I bought competition poly motor mounts and never had a problem again.

If I was only going to do Poly mounts in one location, I would do poly motor mounts and leave the transmission/tcase rubber (just make sure it's not worn out).