NP205 pops out of low

[Honest Bob]

I have a 32 spline figure 8 np205 mounted to a 4l80e using a nwfab 4l80e adapter that keeps popping out of low. Its my first attempt at rebuilding one and I put in new bearings, seals, and shift collars. I suspect the teeth on the gears where the shift collars go on are worn out. I dont know the origin of the np205 but I suspect it had a hard life.

Opinions? Can I still get all these parts or do I need to start looking for a replacement?

Are the internal parts the same between a round pattern and a figure 8 np205?

I have a spare round pattern 91 np205 with the 4l80e adapter. I could use that tcase but I am afraid Im gonna have to have driveshaft lengths modified again.