Driveshaft diameter

[ScottG]

Is there a difference in the driveshaft diameters of a 1/2 or 3/4 ton? I picked up a '69 c10 with a much smaller diameter shaft than my '67 c20.

[crazy longhorn]

How fast do you plan to run it? I have seen a 1/2 ton ,2 pc shaft to almost to 130? The shaft is built for my longhorn(pretty much 3/4 ton spec)...she runs smooth, @ a tick over 140 ...crazyL

[clinebarger]

I think 1/2 ton's are smaller, But as crazy longhorn pointed out these driveshafts are strong, Ive put 500HP through them with no problem, Even broke a pinion on a 9", But not a driveshaft.

[Captainfab]

The smaller diameter driveshafts typically use the carrier bearing that hangs from the top of the trailing arm crossmember. Those carrier bearings are junk IMO. They just don't hold up once you start upping the HP and Torque going thru them. I always go with the heavier duty carrier bearing that bolts to the bottom of the crossmember as you should have in your C20. The C10's were also available with that same HD driveshaft and carrier bearing.

[ScottG]

Originally Posted by Captainfab

The smaller diameter driveshafts typically use the carrier bearing that hangs from the top of the trailing arm crossmember. Those carrier bearings are junk IMO. They just don't hold up once you start upping the HP and Torque going thru them. I always go with the heavier duty carrier bearing that bolts to the bottom of the crossmember as you should have in your C20. The C10's were also available with that same HD driveshaft and carrier bearing.

That's what confused me. My d-shaft had the bearing you described, and the truck I'm parting out has that skinny shaft. Just seemed so dramatically different, I couldn't see how it would hold up.

[sjarrett71]

My last 1/2 ton had the large drive shaft with the horseshoe style carrier bearing. My current 1/2 ton has the smaller shaft with the other style. So I guess they could have either.

[Captainfab]

It has been my experience with the C10's that the trucks with the SM420 4 speed typically had the HD driveshaft and the trucks with 3 speeds or auto trans had the lighter duty driveshaft.

[crazy longhorn]

Originally Posted by Captainfab

The smaller diameter driveshafts typically use the carrier bearing that hangs from the top of the trailing arm crossmember. Those carrier bearings are junk IMO. They just don't hold up once you start upping the HP and Torque going thru them. I always go with the heavier duty carrier bearing that bolts to the bottom of the crossmember as you should have in your C20. The C10's were also available with that same HD driveshaft and carrier bearing.

Yes, that hanger style carrier is the weak point Also that shaft does not have a slip yolk in the middle(pushes /pulls the rubber in the carrier). The shaft itself is plenty strong , for mild to warm street useage tho. after you step up to the 3/4 shaft, with 1350 joints....you will never look back! crazyL

[ScottG]

Originally Posted by Captainfab

It has been my experience with the C10's that the trucks with the SM420 4 speed typically had the HD driveshaft and the trucks with 3 speeds or auto trans had the lighter duty driveshaft.

Now this all makes sense. The truck I pulled it from was originally a 3 on the tree truck, converted to a T10.