Not sure I understand the problem.
IF you are talking about placing the shifter in manual 2nd gear with vehicle at a full stop.... then drive off. The GM design is the 4L60E is in 2nd gear when shifter is in manual 2nd gear position.
The trans will not take off from a full stop in first (1st) gear, then shift to 2nd while the shifter is in manual 2nd gear position
Yesterday is history.