A noise has started coming from the front of my 2000 Mazda Protege. I think I've narrowed it to the transmission, but that answer doesn't make much sense. Here's what I did to diagnose it: Put front of the car on jack stands and removed both front wheels. Used jacks to raise the control arms (and thus axles) to something close to their normal operating position. Started the engine and gently rowed through gears 1-4. I didn't hear anything out of the ordinary. I looked and saw that only the passenger side was turning because of the open diff. I gave a close listen and just heard a little bit of brake noise. Nothing alarming.
Turned off the engine, put the right front wheel back on, and lowered that corner to the ground. This would force the driver side axle to turn. Repeated the steps above and immediately heard the noise I've been hearing. I tried to aim my ear at the noise and it seemed to be coming from the tranny but I couldn't be positive.
Engine off again. To eliminate potential brake noise I removed the left front brake caliper and hung it from the strut and well away from the hub. Engine running again, same noise, so it's not the pads & rotor. No obvious noise coming from the hub area, so that seems to rule out a wheel bearing. The inner axle boot is undamaged and no grease has leaked out.
All this points to the tranny, but why would it only make noise on one side? Any ideas?
