i hope one of you guys can help iam changing the front left driveshaft on my 67 it was throwing grease went to oreillys and exchanged the axle all was well same length same bolt pattern but the axle nut is smaller i understand that it is the same axle on eldorados up till 76 any one know the size ? it is metric seems like a 22.0mm x 1.5mm went back to oreillys and my core is gone

 

I would say they gave you the wrong cv axle. the axle nut should not be metric even on the 78 models. My axles came from napa they did not come with new nuts because the old ones are not lock nuts but use cotter pins so they are reuseable

 

Just got to work (Napa) measured the cv axle on the shelf, looks to be 1 in. 20 thread pitch.