Heard two different positions regarding using polyurethane and rubber mounts on the same drivetrain. On one side I heard you should never have different materials as they each have their own unique properties that could impart more stress on area's of the drivetrain that weren't meant to be subjected to loads. And on the other side I've heard that it isn't that big of a deal because they both do the same job in the same manner. Just the longevity and quality of the two are different.

I have stock rubber engine mounts in place already and am thinking about replacing the tanny mount with a polyurethane one. Ideally I would opt for same same all the way around, and I could just as easily pull the engine out but I was still curious as to what the general consensus is on using different mounts along the drivetrain.

 

IMO it's a myth. I have stock motor mounts and a poly trans mount and have had no problems at all.

 

IMO, The drivetrain will definitely NOT fall apart due to using different mount materials...

Every time a mount wore out, we'd be breaking drivetrain parts if that was true.

 

I've run poly engine mounts with a rubber trans mount in my mustang for over 20k hard miles with no adverse effects

 

I've always heard if running rubber, go same same.
If poly ditto. If alum, ditto. IMO, I think a poly & rubber would play nice. Alum, well I don't need it, but if I did, I'd only run alum. Prolly more important if your runnin mid mount plates & such.

I ran all rubber motor mounts/ tranny. I believe I also did poly on motor mts/ & tranny. I just never mixed cause, well I just didn't.

Anyway, supposedly if you mix, due to the hardness of the poly it will not flex, & the rubber will overflex, & tear. Believe what u like.
I like poly more cause it firms up handling rather than squishy give & it should last longer, rather than how rubber breaks down ( or can).

 

I replaced my tranny mount with a poly mount and it took away the clunking sound I was getting as well. My Camaro has a T56 with poly mounts on the engine and tranny with no problems. I can just feel it more when I grab the next gear

 

i had put a poly trans mount on my old 78 half ton gmc and with rubber engine mounts it only took about a week to completely destroy the poly mount, all that was left was the internal bracing of the mount, all of the poly was gone. i think you should do all or none.

 

What do you think caused it to disintegrate? Did it just get worn to ?

 

sorry about the late response, but i would guess that the old rubber motor mounts allowed more flex than the stiff poly mount could keep up with and it basically over stretched or compressed the trans mount. the poly on my trans mount basically just split and peeled apart.

 

drivetrain probably wont matter but when/if you go to doing suspension bushings, differnet places work better with different kinds of bushings