Is the torque converter the last to lock up in the series of normal shifts? AS 1-2-3-4-converter lockup. Or is it 1-2-3-lockup-4

 

1-2-3-lockup-unlock-4-lockup

 

The 48RE can shift manually like this,

1-2-lockup-unlock-3-lockup-unlock-4-lockup

It can also lockup in second gear as an engine break if you manually shift it into 2nd slowing down. Then just tap the excellerator to lock it.