Low Gear Lock out

[Lancer]

Our Avanti (1983) has the four speed GM transmission and it would seem that it can be manually put from drive (4th gear) into low (1st gear) at speeds that certainly could be harmful to some element of the drive train. My experience is that at about 25 mph the rear wheels lockup in a effort to slow the car which tells me that is much too low a gear to be in at that speed.  I thought all transmissions of the automatic persuasion had built in lock out functions to keep them from being accidently shifted into a lower gear than is safe.  Should I be headed for the transmission shop, or is this normal?