Recently I replaced my motor mount as well as both trans mounts on my 84 fiero. I replaced the trans mounts first and drove the car around a bit before deciding it needed the motor mount replaced as well. After I replaced the motor mount, tons of vibration can be heard in the car. Its like the rubber isolator is too stiff. Do these mounts need to wear in a bit? I know if you cover them in oil ( like my leaky valve cover did for years.....) it will get real soft and gummy haha. Obviously I do not want that to happen.

Are you sure you got rubber ones or poly? Maybe your mounts were that bad before it was like not having any at all.

My duke got worse vibration and noise when I replaced the mount. I believe the original was fluid filled and the replacements are solid. I don't know where you would get a fluid mount now.

I have a manual, so the old one was a solid rubber mount. However, they were hanging on by a thread. They were so torn up they would stretch like a rubber band. I just cant imagine the car would have been sold new as loud as it is inside.

Check to see if there is metal-to-metal contact at the dog bone.

The only thing I can think of is that something solid is "grounded"against the cradle. Bracket? Part of the exhaust system?

Well, the V6 front motor mount was hydraulic.

The '84 has the front engine mount and the torque strut. Did you replace both? It seems there should be a third mount.

Is your new mount rubber, poly, or solid?

quote Originally posted by tshark: The '84 has the front engine mount and the torque strut. Did you replace both? It seems there should be a third mount. Is your new mount rubber, poly, or solid?

Yep, Replaced both the mounts on the trans, the dog bone and the engine mount. All are the OEM rubber.

Raydar, nothing is touching the cradle, but I did replace a few missing exchaust hanger springs with some high tension motorcycle exhaust hangers. That Could be the problem I guess.

I recently replaced all the mounts in my kit car and found lots of vibration. I kept looking at the mounts for some contact with frame and found nothing. It turned out that the through bolt in the dog bone wasn't tightened enough to make good contact with the metal sleeve inside the bushing . The vibration and noise went away after I tightened it.