Tractor Repair: Case 1070, steel clutch plates, shaft bearing

Question
We have a problem with our 1973 Case 1070 tractor. Last year it started slipping in powershift 1 and 2 when taking off, then would suddenly leap ahead. We did the pressure tests on the valve body and it turned out that the c1 piston seal would leak for a few seconds then suddenly seal and pressure up. We split the tractor and found out that the c1 clutch disk was also broken into pieces. We changed the seals and the disk and the tractor worked good for about 100-200 hours (mostly cultivating). Then it started doing the exact same thing again. We split it again today and the c1 disk is again broken up and the teeth around the centre are stripped off. The inside seal on the c1 piston has been damaged and was leaking oil through. Also the tabs on one of the steel clutch plates are bent.
Have you ever seen this problem before? Is there anything else we can do besides changing the disk and seals again?
Thanks.

Answer
 I have seen broken C1 plates many times, but have not had a repeat failure in such a short time as you have.  The entire powershift should be disassembled and checked for other problems.  A loose planetary carrier bearing or output shaft bearing, or broken or missing button bearings will cause the unit to wobble while it's spinning, which can cause lots of damage to other parts of the powershift.