Transmission/Differential Mounts
Thread Starter
Racer
Joined: Apr 2014
Posts: 299
Likes: 26
From: N. E. Texas
Transmission/Differential Mounts
I installed a Pfadt style differential mount, then removed/sold because I didn't like the added vibrations in the cabin. Then I bought/installed a used Hinson poly differential mount. It's currently in my '02 C5Z. Not as much vibration transmitted to cabin. Here's the question: With each mount installed I get a fairly violent vibration forward near the bell housing area during hard acceleration. Felt like the front end of the drive train was hitting the floorboard. This was different from the rear shake that I would get with the stock rubber differential mount. I'm theorizing that the stiffer rear mount causes the rubber engine mounts to shake. Should I install poly engine mounts to enhance the stiffness of the poly differential mount? (Not interested in solid engine mounts.)Shoot me some opinions.
Racer
Joined: Jun 2004
Posts: 270
Likes: 67
From: Montana
Did you measure the height of the diff mount? If it slightly taller it can push the torque tube closer to the tunnel frame...the shifter mount to tunnel frame is closest contact point... I installed non oem diff mount and the gap went from 1/4” to 1/8”.... on aggressive acceleration it would bang loudly...
Melting Slicks
Joined: Dec 2018
Posts: 2,663
Likes: 1,389
From: Orange County, CA
Recently I did a transmission synchro rebuild, rear main seal+cover and full clutch job, torque tube rebuild, and LSD rebuild. I also put in the Hinson poly diff mount.
Afterwards there was some noticeable vibration that I don't think was present beforehand (though the car was down for 3 months, I could've forgotten).
I too surmised that there could be extra stress on the stock/original(?) motor mounts, so I bought some inexpensive replacements off RockAuto. Haven't installed them yet, though.
If motor mounts don't resolve this for me, I'll get a new stock-style diff mount. The extra performance of the Hinson poly mount isn't totally necessary since the car is mostly a DD. The small amount of added vibration would be totally acceptable if it was a weekend driver or track type car.
Afterwards there was some noticeable vibration that I don't think was present beforehand (though the car was down for 3 months, I could've forgotten).
I too surmised that there could be extra stress on the stock/original(?) motor mounts, so I bought some inexpensive replacements off RockAuto. Haven't installed them yet, though.
If motor mounts don't resolve this for me, I'll get a new stock-style diff mount. The extra performance of the Hinson poly mount isn't totally necessary since the car is mostly a DD. The small amount of added vibration would be totally acceptable if it was a weekend driver or track type car.
