Drivetrain vibration after installing poly trans and torque arm mounts

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Jul 20, 2008 | 04:35 PM

mike_c

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From: Fallston, Maryland

Car: 1989 Trans Am GTA

Engine: 350

Transmission: T56

Axle/Gears: 9 Bolt 3.70

Drivetrain vibration after installing poly trans and torque arm mounts

A few weeks ago I replaced the transmission and torque arm mounts with polyurethane units. After replacing the mounts, I've been getting an occasional vibration. It doesn't seem happen at any particular RPM, speed, or gear. The only time it doesn't happen is when it's in overdrive. It can be vibrating while I'm in D and when I put it into OD, it stops. Do the poly mounts just transmit more vibriation through the body, or did I just put it back together wrong? There weren't any vibrations with the old mounts before I replaced them.

Jul 20, 2008 | 05:23 PM

$//<86TA>\\'s Avatar$

//<86TA>\\

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From: Central NJ

Car: 86 Trans Am

Engine: 408 stroker sbc

Transmission: TKO600

Axle/Gears: Moser full floater m9, 3:70 trutrac

Re: Drivetrain vibration after installing poly trans and torque arm mounts

its normal to pick up some vibration with poly mounts. they dont absorb them as well as the mushy rubber ones did.

Jul 20, 2008 | 06:00 PM

JamesC

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From: Lawrence, KS

Car: Met. Silver 85 IROC/Sold

Engine: 350 HO Deluxe (350ci/330hp)

Transmission: T-5 (Non-WC)

Axle/Gears: Limited Slip 3.23's

Re: Drivetrain vibration after installing poly trans and torque arm mounts

Quote:

Originally Posted by //<86TA>\\

its normal to pick up some vibration with poly mounts. they dont absorb them as well as the mushy rubber ones did.

86 is on the money. The vibration/harmonic problem was so severe at high RPM's with poly secondary mounts that I couldn't take it and swapped those out with new rubber (though the main mount remains poly). Now, much better.

JamesC