This has been an issue since swapping the SR axle and using the GenII progressive coil springs. It is apparently a problem for others. Eddy and I had discussed possible remedies for this many moons ago. I'm just now getting around to doing something about it.

Here are my angles currently...

At the T-case:



At the pinion flange:




We were talking about elongating this hole



to be able to rotate the entire diff. That should change the pinion angle sufficiently. We shall see...

Have you tried a search? It might have been discussed before. <img src="/forums/images/graemlins/zombie.gif" alt="" /> ( <img src="/forums/images/graemlins/lol.gif" alt="" />)


That truck's never coming off it's stands.

Did you measure the pinion flange angle with the wheels on with the truck on the ground with a normal load and a driver in the seat? Also did you measure the angle at the txfer case with the engine fully assembled and everything in place up front?
John

Brendan, no I didn't search. I feel more manly when I don't. And yes, fu**head, it will be coming off the stands. Eventually.




Definitely before I sell the house.






John, everything is together sans driveshafts. And the angles I'm getting are the same as I got with tires on the ground, loaded as usual with 3 80lbs bags of sand in the driver's seat (which is within 100 lbs of my actual weight <img src="/forums/images/graemlins/smile.gif" alt="" />.)

I had already taken that stuff into account. I've been stewing on this for a couple years now. Your Dad and I figgered if I could get them within 1 degree or less of each other that'd be good enough. Your thoughts?

I laughed pretty hard when i read your response. Thanks <img src="/forums/images/graemlins/lol.gif" alt="" />

Id just run it. No sense in possibly making more problems. If its not eating joints...
John

It hasn't been eating them per se. More like chewing or gnawing at lightly. And the hum at ~60-65mph is annoying as hell...

I don't see where it'll create more issues. If it doesn't work, I'll simply put it back where it was. Am I missing something in that plan?

Are you sure the shaft is balanced and mounts centered? Just checking.

My most recent research says no more than 1/2* difference in the angles.

The measurement I saw used was to install the ujoints and driveshaft, and set the slip yoke and pinion yoke to 6 ans 12 oclock. Put a socket of proper size on the bearing cap to get gauge clearance and measure the angle of the socket.

Diagrams and add'l info is here.

More stuff here on max ujoint angles vs shaft speed:
SHAFT RPM OPERATING ANGLE
5000 3.25?
4500 3.67?
4000 4.25?
3500 5.00?
3000 5.83?
2500 7.00?
2000 8.67?
1500 11.5?

Now consider that with our a/t's, the dshaft is rotating FASTER than the engine. for example, with a .70 od ratio, at 2800rpms, the shaft is doing 4000rpms, so the angle limit is 4.25* I think ours exceeds that. The result is shortened ujoint life. Average life is 3000hrs. Doubling the angle halves the life, and differences in angle also shorten the life, but I haven't found a factor for that yet.