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.

 

MY SECOND POST FOR YOUR PROBLEM; I WANTED TO EXPLAIN THE BEARING FAILURE AND WHY FOURTH GEAR IS DIFFERENT.
ALL LUBRICANTS NEED TO BE CHANGED, EVEN SYNTHETICS. THIS IS A MAINTENANCE ISSUE, NORMAL GEAR FLUIDS EVERY 30K AND SYNTHETIC
AT 60K ARE COMMON MILEAGE INTERVALS. OF COURSE ANY LEAKS OR EXTREME DRIVING HABITS WILL INCREASE THE WEAR AND TEAR ON
THE TRANS.
THE REASON THE NOISE CHANGES IN FOURTH: INPUT SHAFT IS SPLINE TO THE CLUTCH DISC; WHEN ENGAGED THE INPUT SHAFT TURNS THE
CLUSTER GEAR WHICH TURNS ALL YOUR FORWARD FREE WHEELING GEAR ON THE OUTPUT SHAFT.
eg. POWER FLOW IN SECOND GEAR; INPUT SHAFT TO CLUSTER SECOND GEAR , TO SECOND GEAR WHICH YOU LOCK TO THE OUTPUT SHAFT
WHEN YOU SHIFT, FROM OUTPUT TO DRIVE SHAFT.
WHEN YOU SHIFTED TO FOURTH GEAR, YOU LOCK THE INPUT AND OUTPUT SHAFTS TOGETHER. THIS DECREASE THE BEARING LOAD BECAUSE
THE POWER FLOW IS NO LONGER GO THRU THE CLUSTER GEAR, ALSO OUTPUT SHAFT IS LONGER AND SUPPORTS MORE OF THE LOAD.
** NB. OTHER MEMBERS: NOTE THIS IS THE SAME FOR MAZDA REAR WHEEL DRIVE VEHICLES; OLDER 626, GLC, ALL RX'S, B SERIES (MAZDA) AND
MIATA'S WITH MANUAL TRANSMISSIONS. **