518 46re smoked

When you put a TF in Manual Low, you lock the rear drum stationary. When you put a TF in Drive, the sprague does a similar job.
The sprag is not meant to be abused by towing, neutral-drops or racing. It provides a bit of a cushion when selecting Drive-low.
When you downshift a TF from second to first, You are engaging the L/R band. Same for the KD 2-1 shift.