There might be some "bench adjustment" which the rebuilder can obviously do so all works well, but "something happened" with your box somewhere.
The issue with the Dodge pickups is NOT the same as this issue. The "death wobble" happened AFTER a wheel hit a bump, not just starting the vehicle. I also suspect that many of these issues on the pickup chassis happened after the trucks were "lifted" on the suspension for a higher ride height.
The "centering" adjustment is not rocket science, as I understand. The service manual procedures seem reasonable in how they operate. The mechanics I talked to about it, back then, had no issues with fluid leaks (that they mentioned), but they were dealing with vehicles which were a few years old, rather than "decades" old, if that matters in this case.
When everything is centered, everything should operate "as designed", although the self-turning issue is also "as designed, but not best-adjusted".
As I recall, the techs used a metallic hammer to do the tapping with. You're only using enough force to move things a little bit at a time. Once you get things started, with each tap, you might determine how many more are needed, I suspect.
For good measure, go just past where the wheel wants to turn the opposite direction, then go back to where it stays centered.
CBODY67
The issue with the Dodge pickups is NOT the same as this issue. The "death wobble" happened AFTER a wheel hit a bump, not just starting the vehicle. I also suspect that many of these issues on the pickup chassis happened after the trucks were "lifted" on the suspension for a higher ride height.
The "centering" adjustment is not rocket science, as I understand. The service manual procedures seem reasonable in how they operate. The mechanics I talked to about it, back then, had no issues with fluid leaks (that they mentioned), but they were dealing with vehicles which were a few years old, rather than "decades" old, if that matters in this case.
When everything is centered, everything should operate "as designed", although the self-turning issue is also "as designed, but not best-adjusted".
As I recall, the techs used a metallic hammer to do the tapping with. You're only using enough force to move things a little bit at a time. Once you get things started, with each tap, you might determine how many more are needed, I suspect.
For good measure, go just past where the wheel wants to turn the opposite direction, then go back to where it stays centered.
CBODY67