mainshaft nut size.

[69jeepcj]

I had a disaster a few weeks ago, I stripped the main gear on my overdrive unit on my dana 18 T/C. I took out the overdrive for now (too expensive to fix at this time) got a stock D18 gear to replace the OD but I do not have the washer or nut that holds it on. Can anyone tell me what size this nut is?? Going to tracktor supply to try and get one. Any suggestions? thanks
Oh, this is a 10 spline shaft

 

[Saddle Tramp]

Contact Herm; he is the guru of Spicer 18.

http://www.hermtheoverdriveguy.com/index.htm