Rebuilt 904. Whirring. Dead?

Thanks man. My convertor was set inside the trans by the trans builder and held in with a piece of aluminium flat bar. I simply removed the flat bar and installed the trans/torque converter to the motor/flexplate.

i used all new bolts etc. nothing was snagging or rubbing anywhere.

I never had it out of first gear so I don't know how well it shifted if at all lol.

Does anyone know what the possible cause for a front planetary failing could be?

Would it be very likely that it would be caused by running at 5-10mph for 30 seconds with low fluid level?

Or is it more likely either a faulty/worn component or a mistake during assembly?

or is it hard to accurately say?

Thanks again guys.