Driveshaft thread size?

[elan23]

Anybody know what the driveshaft thread size is in the middle of the shaft? Tried various, 8mm and 10mm it ain't. Need to know to be able to pull the shaft that extra 2mm to get the circular on, (trying to fit HD flanges.
Thanks.

 

[Paul D]

Don't know definitely, think it's 3/8 unc, but I use one of the flange bolts, pushed in then lever against the threads to pull it out. If that won't do it there's something stuck, the shaft should move on the splines quite easily.