These are the technician notes from the diagnostic workup:

-Move shift to D and N; truck has worked well since
-Chirping sound between park and reverse with harsher engagement park to drive
-No MIL lights
-Note: Transmission is equipped with Protect68 kit, TCM tune for 250 PSI line pressure and 30hp increase
-Transmission issue; Heard a bang noise at 20KPH
-Lost all forward and reverse. Move shifter park and drive; engine revved and no go (shut off truck), put in N and Drive and then worked

TECH NOTES:
Start truck and has forward and reverse
-Road Test; no problems with transmission
-Check fluid level & it is a little low; fluid feels a little thicker than normal
-Check for leaks & none seen; scan for transmission codes and none found
-Take on longer road test & still had no trouble
-Road test after transmission fluid / filter service was completed and two codes came back
-Code P0841 Low reverse pressure switch rationality & P1775 Solenoid Switch Valve Latched in TCC Position
-Cleared codes and road test again
-Cannot get transmission converter to lock up
-Code P0841 came back when shifter was put in neutral after road test
-Perform some tests and look like there may be internal leakage & a possible problem with the solenoid pack

Providing the notes to help with clarification on what was found.