I have this conversation very often with customers. Thrust issues are more common than you might think, but like many things it is a combination of things that can cause this problem. What you need to understand is that this is a hydraulic problem. It is crank lubrication/VS torque converter charge pressure. On one end you need good lube pressure to the rear of the main bearing; normally all that you get is what runs off the main bearing so I recommend chamfering the bearing at the upper half to make an oil port to pump direct oil to the thrust. On the transmission end high line pressure can over charge the torque converter causing it to push harder than the lube on the thrust can handle. It is a balance between the two that you need to achieve to alleviate this problem.
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