getrag issues

[odee]

Just got my 86 gmc dually back together with the new clutch for the cummins. Was able to put about 125 miles on truck to find the getrag main shaft broken at the nut threads on rear yoke. Whst would or could have caused this? Would it be possible to drill and tap the shaft for say a 7/16 fine bolt and hard washer to holt it together like the nut did? Other opinions on what to do. thanks

[ellis93]

Over tightened at one time,bad u joints or out of balanced shaft vibrating....or just poor metal and it fatigued. Who knows.

As for Drilling and tapping,it'll be real tough. I've never tried to drill a getrag shaft but I've tried to dimple a nv4500 shaft for a fancy 5th gear nut.....it was a bitch.

[odee]

Well after some thinking was able to use a socket,square tubing,and a sized punch to get a good center mark. Shaft drilled alot easier than expected with a good bit. Tapped out well also. Just have to put drive shafts back together and in. Hopefully this will holdup till I can round up parts for a nv4500 swap.