Bizzare Vibration

[drugal]

I need some help figuring out what's making my car vibrate. 1987 Gen2 3S-FE 5spd.

When I let off the gas and let the car slow down in any gear at any speed, I get a loud, heavy buzzing vibration from the front. I get the same vibration (but more harsh) maybe 1/10 times when I accelerate from a stop, and it goes away when 10-20km/h is reached. This vibration tends to stutter in and out.

If I push the clutch pedal in, or put it in neutral, it goes away immediately. I can feel it very faintly when driving normally in gear. This vibration doesn't happen while the car is at a stand-still, either in neutral or with the clutch pushed in.

Thing's I've checked:

Replaced flywheel and a new clutch kit
Replaced transmission
Replaced axles
Replaced front steering knuckles

These symptoms don't fit a bad pilot bearing (idles perfectly), and I'm at my wits end trying to figure out what's going on with it.

[Reppinshadyvill]

Maybe the input shaft of the tranny? Did you apply a light coat of hightemp grease?

[fredk]

motor mounts

[white90dx]

Sounds like motor mounts or something interferring when the motor twists on accelleration. Check the mounts and check if anything could be getting in the way as the motor twists when torque is applied.

-Charlie

[drugal]

I greased up the input shaft on the new tranny, and I checked all the mounts when I replaced it. They appear to be fine, and nothing is rubbing on the axles.

I've checked the timing belt area, pumps, and bearings. The steering pump was replaced.

The frequency of the vibration is related to engine speed, and it definitely is something related to the engine's torque being in contact with the rest of the drivetrain.