Pitman Arm Washer or Lock Washer

[500stroker]

I have a 66 Satellite with power steering. My question: Is there suppose to be a thick washer or a lock washer under the big nut that secures the pitman arm to the steering box output shaft?
Thanks in advance

 

[35desoto]

All the ones I have taken apart have all had the large spring loaded washer under the Nut. Yes there is suppopsed to be a thick spring steel washer between the pitman arm and the nut