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1310/1350 U-Joint question.

Gunner1

Gunner1

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Ok. I bought a new 489 case with 3.73 gears and a Detroit locker. I also added a billet pinion Yoke in 1350. My old unit was a 1310. I didn’t have a local shop here that could make me a new full 1350 shaft. Problem I’m having is a vibration that’s new. I’ve never used this kind of joint before. The 1350 and 1310 caps don’t run on the same shaft length. The 10 caps are about 1/2 inch forward of the 50 caps. I’ve got jackstands on the axle housing and the shaft seems to run true. Phasing didn’t change unless it did because the two axle stubs on the joint are not in sync. Maybe a bit of fore and aft. It’s not real bad but at 75 to 80 I can feel it getting stronger. I have broken a. Shaft before without a loop. I don’t want to have that happen again.
 
Having trouble following what your problem is. You have a 1350 yoke on rear diff right. Your driveahaft is what u-joint? Some pictures might help.
 
I’m confused too. This is a 1310/1350 combo u-joint. Does yours not look like this?

IMG_0068.png


Or are you saying the 1310 yoke is shorter than the 1350 yoke, pulling the driveshaft 1/2” further out of the transmission?
 
Maybe it's a speciality conversion joint with an offset between the 1310 and 1350 sides to allow for more operating angle?

Grant
 
Sorry. Should have been clearer. With the joint in place the 1350 post fitted in the yoke saddle the 1310 posts sit almost 3/8th towards the front of the car. It is not inline like the picture AS67GTX showed. If I layed mine on a table with the 2 1350 cups touching the surface the 2 1310 cups would sitting above the table surface by 3/8. Then it just might be my shaft needs a balance. I went from a 2.94 to a 3.73 so my shaft speed is greater at 70 now. I think I’m going to order that joint he posted.
 
I’ve never seen a joint like that. Can you post a picture of it sometime just for my curiosity?

For the vibration - have you checked the transmission yoke and tail bushing for wear? Once they develop some looseness they will cause a vibration issue. The bushing can be changed without removing the tail shaft. But either the yoke or bushing, or both, can be worn.
 
Gunner1 said:
Sorry. Should have been clearer. With the joint in place the 1350 post fitted in the yoke saddle the 1310 posts sit almost 3/8th towards the front of the car. It is not inline like the picture AS67GTX showed. If I layed mine on a table with the 2 1350 cups touching the surface the 2 1310 cups would sitting above the table surface by 3/8. Then it just might be my shaft needs a balance. I went from a 2.94 to a 3.73 so my shaft speed is greater at 70 now. I think I’m going to order that joint he posted.
Click to expand...

The cap diameter is different, that’s why when sitting flat on your bench, the 1310 caps don’t touch. 1310 is 1.063” and 1350 is 1.188” cap diameters respectively. The trunions of the u-joint will share the centerline of the u-joint…they have to.

I understand you bought a 1350 yoke for your carrier housing, which is the most common ‘go to’ for higher horsepower and/or drag racing but am questioning that you actually had a 1310 originally in your car. The Detroit series joints, either 7260 or 7290 were much more prevalent in our cars.
 
Try moving front yoke up and down, there should be very little movement if .010" or more bushing needs changing.
 
Still sounds like a speciality joint for the rock crawler crowd with offset between the two sides to allow for more articulation.

Grant
 
Vitamin_A12 said:
The cap diameter is different, that’s why when sitting flat on your bench, the 1310 caps don’t touch. 1310 is 1.063” and 1350 is 1.188” cap diameters respectively. The trunions of the u-joint will share the centerline of the u-joint…they have to.

I understand you bought a 1350 yoke for your carrier housing, which is the most common ‘go to’ for higher horsepower and/or drag racing but am questioning that you actually had a 1310 originally in your car. The Detroit series joints, either 7260 or 7290 were much more prevalent in our cars.
Click to expand...
That’s correct. The trunion posts do not intersect if you lay it flat on a table and look from the side. I’m looking for a picture.
 
Ok I pulled the bill from the shaft shop. Now I’m really confused. It says he used a Spicer 5-789x which is a 7260 series joint. He told me he used a 1310/1350 hybrid. My mechanic had no problems with the install. Guess I’m gonna see if I can get down on the creeper. Passed out, fell and broke my tailbone Sunday. Moving slower than usual.
 
Yeah. Standing b/p is running in the low 70s. Parkinson’s is messing with my med requirements. Cars in the big garage. I’ll get my grandson to help me get up and down.
 
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