1986 Syncro 120K miles. History unknown.

My transmission has just started making (or I have just noticed)what
I call a growling sound at very low speeds and while stopped.

The most easily replicated symptom is:

1. Start the engine with the transmission in neutral and
        let it warm up.

2. At a full stop, depress the clutch pedal.

3. Shift into first gear. Do not release clutch pedal.

4. The growling sound starts, and continues while in gear.

5. Release clutch pedal and drive away normally.

6. Growling continues, but lessens with speed. Growling stops at
        about 8-10 MPH.

7. Repeat steps 2 & 3 in second gear.

8. Same as #4 above.

Anybody know whats up? Should I stop driving it immediatly?

Thanks,

John-Reed Maffeo