U joint confusion

[TJ1978]

For 69 c10
I have confused myself on this
GM 12 bolt rear what U joint size? They said it’s 1310 from differential pic but I’m not sure. Doesn’t look like 1330 and certainly not 1350

 

[TJ1978]

..

 

[nvrenuf]

When you're measuring the yoke, get the distance between the retaining tabs - not the overall width.

Iirc, a 1330 should be longer on one side where 1310 & 1350 are the same width on both sides of the cross.

 

[TJ1978]

I am horrible at math especially fractions.
So...

 

[frankin5]

What is the distance from inside of tab to the opposite inside of tab on the yoke? Measure outside to outside on u joint. What is the diameter of the u joint cup?

The 1330 and 1350 both measure approximately 3 5/8 wide. The 1310 and 1330 series can have cap diameters of 1 1/16 and/or 1 1/8 inch or a combination of both sizes. The 1350 series has a cap diameter of 1 3/16 inch and the body and journals are bigger than the 1310 or 1330.

 

[TJ1978]

The digital read is screwy so..

looks/measures 1310 to me...

 

[frankin5]

looks to be 1310 or the corporate joint, 3r or something on that order. Dennys driveline
Driveshaft and Driveline Parts > Universal Joints > U-Joints BY SIZE > 3R Series U-Joint 2.556 X 2.556 - 1.125 inside c clips > 1.125 X 1.125 Bearing Cap ...
this is a combination joint
1310 to 3R series Combination Universal Joints · 2.556 inches wide between the yoke inner surfaces where the "C" Clips lock in. · 2 bearing caps are 1.125 inch (1 ..

 

[TJ1978]

I was on so many different websites including the one you quoted from. Just made everything even more confusing.

what prompted the frantic posting/searching is, I ordered my driveshaft today and after measuring, talking with them and sending pictures, I got worried I may have ordered incorrectly.. Driveshafts aren’t cheap so... hahahaha

Thankfully, they are local in the event any issues arise.
@frankin5

 

[sweetk30]

the 2 tiny taps 1 per side the cap touches . NOT the u-bolts or body of the area the u-bolts go in .