944na driveline noise

[porschepoodle]

84 944na...Trans/diff fresh $3k rebuild. Balance shaft retimed. Vibrations/rattle/noise at rear of car at idle and very noticeable when decelerating under compression. Mechanic says it is torque shaft bearings. When in the drivers seat noise is similar to a differential bearing noise. Any input would be appreciated.

[Gawernator]

Torque shaft is the same as Torque tube?

[wrench1]

Let the car idle in neutral and see if you have the noise. Then depress the clutch and place in gear, noise gone? If the noise goes away with the car sitting still, in gear and clutch depressed, it's the torque shaft bearings. If no noise sitting still in or out or gear and only with car moving, most likely the rear wheel bearing(s).

If there is no noise either in gear or out of gear, with clutch depressed or engaged you may have lost the pinion shaft bearing or the pinion depth may not have been set incorrectly when the differential was rebuilt.

Hope this helps out.

[kachunk]

When my torque tube bearings went, it sounded like a rattling near the catalytic converter area. When pulling from a stop it rattled when clutching. It sounded like hitting a frying pan with a hammer rapidly.

I wish I took a video of the rattle, but this is just the bad bearings with no load on it. I took this video after removing the transmission. Camera is sitting under the drivers door. I could turn the noise on/off by clutching.
With no load on it it just sounded like sand in the bearing. Turns out the front torque tube bearing was completely shot and just grinding to pieces.

Try Wrench1's advice to determine where in the drivetrain its coming from.

[Guest765]

Originally Posted by wrench1

Let the car idle in neutral and see if you have the noise. Then depress the clutch and place in gear, noise gone? If the noise goes away with the car sitting still, in gear and clutch depressed, it's the torque shaft bearings. If no noise sitting still in or out or gear and only with car moving, most likely the rear wheel bearing(s).

If there is no noise either in gear or out of gear, with clutch depressed or engaged you may have lost the pinion shaft bearing or the pinion depth may not have been set incorrectly when the differential was rebuilt.

Hope this helps out.

This isnt really true. It could still be the throwout bearing because putting pressure on the otherwise free running bearing changes the characteristics of the bearing and how it engages the wear groove causing it to shut up. Only way to know 100% is to pull the tranny and rotate by hand.

Edit; the TO bearing typically stops spinning when the clutch is pressed also but older ones tend to keep spinning regardless

[Gawernator]

My TT bearings aren't so healthy, I wonder if my rattling exhaust type sound is the same thing. Yours is a lot worse though and sounds just like a pan. I don't think my sound goes away either with the clutch in.