E-Bodies.org Cuda Challenger Forum

Technical Shop => Engine, Transmission & Rear End => Topic started by: Scooter on February 27, 2021, 11:34:53 AM

Title: Transmission mount 727... Poly vs. Rubber?
Post by: Scooter on February 27, 2021, 11:34:53 AM
Have a lil interior vibration left over after replacing the u-joints a week or so back. Prior owner installed a poly transmission bushing and I'm thinking it might be the culprit. Anyone on-board have real world experience going to or from rubber/poly and picking up additional seat of your pantelones vibrations?

:dunno:
Title: Re: Transmission mount 727... Poly vs. Rubber?
Post by: 1 Wild R/T on February 27, 2021, 01:14:42 PM
I run a poly mount with no vibration issues... I had a vibration, till I corrected the pinion angle....
Title: Re: Transmission mount 727... Poly vs. Rubber?
Post by: 7212Mopar on February 27, 2021, 03:23:17 PM
Changed from broken worn rubber to poly mount and no vibration.
Title: Re: Transmission mount 727... Poly vs. Rubber?
Post by: Scooter on February 27, 2021, 04:49:36 PM
^^^ Thanks both. Thinking some of it might be from the poly-lock motor mount on the driver side as well.
Title: Re: Transmission mount 727... Poly vs. Rubber?
Post by: Chryco Psycho on February 27, 2021, 09:48:54 PM
Could be a number of things like trans rear bushing worn , driveshaft angle , bad U joint .
the mount will not create a vibration but you might feel it more with poly .
Title: Re: Transmission mount 727... Poly vs. Rubber?
Post by: BigSig 6 Barrel on February 28, 2021, 07:37:11 AM
Quote from: Chryco Psycho on February 27, 2021, 09:48:54 PM
Could be a number of things like trans rear bushing worn , driveshaft angle , bad U joint .
the mount will not create a vibration but you might feel it more with poly .
.

For sure C/P . . .  I see this all the time in the motorcycle world . . . and I'm not saying that's the case here, but so many people focus on fixing the "symptoms", not realizing that they still haven't addressed the root "problem".

.
Title: Re: Transmission mount 727... Poly vs. Rubber?
Post by: HP2 on February 28, 2021, 08:49:39 AM
Agree its not the mount but poly could make it more noticeable.

I've never used a poly trans mount and have always preferred rubber. The  tail shaft on a transmission isn't exactly the strongest thing, so I have always used rubber to allow it to flex some if needed.
Title: Re: Transmission mount 727... Poly vs. Rubber?
Post by: anlauto on February 28, 2021, 09:06:08 AM
I was always told you shouldn't mix rubber (engine) mounts with Poly (transmission) mounts....same with suspension, you should never mix the two  :dunno:
Title: Re: Transmission mount 727... Poly vs. Rubber?
Post by: Scooter on February 28, 2021, 10:39:44 AM
The drivers side motor mount is a poly lock.. passenger is regular rubber. Switching that one motor mount to rubber took quite a bit of vibration down, the new u-joints near eliminated it. Wondering if what's left is "normal" but highlighted by the stiffer mount(s)? Transmission was rebuilt some time back and has maybe 10k miles on it.