I have my rear drive shaft off my 74 (doing t-case output bearings) and noticed something puzzling to me.
The rear sliding spline chamber seems to be airtight. I could not push in the spline end of the shaft without releasing air by taking out the grease nipple. My front drive shaft spline chamber is vented into the middle of the yoke – this slides easily.
My concern is under rear axle compression when the drive shaft moves forward along the splines, this pressurized air chamber exerts pressure on the transfer rear output shaft bearings in a forward direction. And when the rear axle goes down, the spline chamber resists the backward sliding spline section (like a vacuum) and exerts a pulling force backward on the T-case output flange backward. So you can visualize while driving over undulating terrain this would cause forward and backward pulling stresses on the rear T-case output flange as the airtight chamber in the drive shaft resists ‘compression’ and ‘expansion’.
My question is – why isn’t this chamber vented to equalize air pressure ??
I am wondering if this addition pushing and pulling stress on the front spline section and onto the T-Case output flange has contributed to the premature failure of my T-Case output bearings (front and back bearings and races were worn with relatively low mileage 130k).
The wear pattern on the front and rear races (t-case rear output shaft bearing) would appear consistent to the output shaft rocking back and forth due to these back and forth stresses as I have described above.
If the driveshaft spline chamber supposed to vented?
The rear sliding spline chamber seems to be airtight. I could not push in the spline end of the shaft without releasing air by taking out the grease nipple. My front drive shaft spline chamber is vented into the middle of the yoke – this slides easily.
My concern is under rear axle compression when the drive shaft moves forward along the splines, this pressurized air chamber exerts pressure on the transfer rear output shaft bearings in a forward direction. And when the rear axle goes down, the spline chamber resists the backward sliding spline section (like a vacuum) and exerts a pulling force backward on the T-case output flange backward. So you can visualize while driving over undulating terrain this would cause forward and backward pulling stresses on the rear T-case output flange as the airtight chamber in the drive shaft resists ‘compression’ and ‘expansion’.
My question is – why isn’t this chamber vented to equalize air pressure ??
I am wondering if this addition pushing and pulling stress on the front spline section and onto the T-Case output flange has contributed to the premature failure of my T-Case output bearings (front and back bearings and races were worn with relatively low mileage 130k).
The wear pattern on the front and rear races (t-case rear output shaft bearing) would appear consistent to the output shaft rocking back and forth due to these back and forth stresses as I have described above.
If the driveshaft spline chamber supposed to vented?
