131k miles 5spd non turbo. no leaks, no indication of a problem before. this morning approx 80mph car started chugging and making grinding and whirring noise in 5th gear...subsequently had same problems in all gears, much less in 4th though. when at idle with clutch engaged makes same noise. what could my problem be...syncros, clutch plate??? my only transportation and i work 67 miles from home. need advice bad. thanx in advance

 

YOUR TRANS HAS HAD A BEARING FAILURE; EITHER INPUT SHAFT AND/OR CLUSTER
GEAR SHAFT, ON WHICH THERE IS THREE BEARINGS.
YOU'LL NEED TO REBUILD OR REPLACE; CONTINUE USE WILL ONLY CAUSE MORE DAMAGE.

 

I agree with that. Probably less noise in 4th because it is direct drive so there is no power load on the counter shaft.

 

By clutch engaged do you mean clutch pedal is depressed or released? If pedal is depressed then the trans gears should not be turning at all and you probably have a seized up pilot bearing. If it is with pedal released then the input shaft bearing has probably failed. Weakest part of the transmission is that input shaft bearing.