Need transmission problem diagnosis..., Or best guess Options

[Porsche Rescue]

Started my '70 tail shifter this morning, attempted to engage reverse and heardf/felt a horrible grind (kind of like the clutch pedal was not depressed, but it was). Quickly returned to neutral and tried again. I engaged reverse OK and backed out of the garage. But I heard a grinding/growling noise while moving and felt the sensation of something restricting movement (like brake on, but it wasnt'). Moved it back and forth in the driveway in all gears. It makes the same noise in all 5 forward gears as soon as I release the clutch. Reverse now seems almost OK.

Where do I start? Could it be a linkage issue (the front two bushings were new a few months ago)? It shifts smoothly when clutch pedal is depressed. Is something broken in the tranny? All opinions welcome.

[Katmanken]

Ok, let's think this through.

Tranny is out of gear and clutch pedal is released. At this point the clutch disk is compressed into locked engagement with the flywheel by the pressure plate. This causes the maishaft and attached gears in the tranny to spin at the same speed as the engine. The mainshaft gears spin the unengaged gears on the secondary pinion shaft without spinning the pinion shaft.

Push in the clutch and the throwout bearing engages the pressure plate. This moves the pressure plate away from the flywheel and disengages the clutch disk from the flywheel, pressure plate ,and rotating engine. At this time, the mainshaft in the tranny is disengaged from the rotating engine and can stop rotating. But one end of the stopped main shaft is rotatingly engaged with the shaft bearing in the flywheel.

Now you engage a gear and let out on the clutch and the growling noise happens. Is it ONLY when the tranny is in gear? Does it ever occur when the tranny is not in gear?

When you engage a gear and let out on the clutch, the pressure plate begins compressing the clutch disk between the rotating flywheel and the non-rotating pressure plate. At this point, the clutch disk slips to bring the non-rotating mainshaft and tranny up to engine rotation speed. Once the pressure plate is fully released, the clutch disk should be locked to the flywheel. That is, spinning with the flywheel and it shouldn't slip. In the tranny, the main shaft should be spinnining at engine speed and the engaged gears should be spinning the pinion shaft at a speed related to the selected pair of engaged gears (gears 1-5). At this point the ring gear in the differential is engaged with the pinion and should spin the axles.

I see two things, if the emergency brake is stronger than the clutch and locks the intermediate shaft so the clutch disk spins, the clutch disk and pressure plate are toast.

Next, I'd look at whatever is connected to the pinion shaft. Why? because whenever the pinion shaft is engaged to the intermediate shaft, the noise happens.

Which brings up a question- gone into the differential yet? Rings and pinions growl and whine when going, and the bearings in the differential that support the axle plates could be the culprits. Hows about the spider gears?