So... I believe I did this correctly. I measured the angles of my driveline and got the following degrees of drop, front to rear. I think I entered the rear end yoke right. The yoke is angles up, so it follows the same angle of the driveshaft. I don't mean with the same degree of slope as the driveshaft, but I mean sloping in the same direction.
Trans 4* down
Front driveshaft 2* down
Rear d.shaft 4.5* down
rear end yoke 3* up or down. I'm guessing I entered it correctly because entered as sloping down it lessens the degrees of angle and that makes sense. What concerns me is that the center angle where the two shafts join is 2.5*. If I lower the carrier bearing a bit, that angle will decrease, but the first angle, from trans to shaft #1 will increase. So, I'm hoping to get a bit of guidance here. Should I change it at all? Depending where I read online, I can either have 2* max or 3* max. What do you guys say? Knowing I only get a rattle when I lug it.



Now that I look at the calculator, it seems that dropping the center carrier bearing bracket would increase the drop angle degrees of the front shaft, and that would decrease the degree of angles of both the front and center joints. I think that is the route I will go. We shall see.

 

You only get a rattle when you lug it? Did you say that previously and I missed it?
A rattling transmission is very common when you lug an engine too far because of the harmonics coming through the crankshaft of the engine. Just putting it under load is one thing, but actually lugging it is a whole nutha thing!

However, even though I can't really see in your last pics because they're a little too close in most cases, that first one does make it look like the angles are off. They're not extreme in a binding sort of way, but it looks like the rear pinion points slightly "above" the driveshaft. Is that right, or is it just the angle of the camera?
Unless I'm getting my angle information skewed (and I don't think I am?) when the driveshaft is slightly "down" from the front joint (middle joint in this case) then the rear joint has to be "down" as well.
This is all referenced from an imaginary centerline through the driveshaft. So if the front driveshaft as it exits the carrier bearing is pointing "over" the top of the rear driveshaft, then the rear pinion shaft must point "below" the centerline.
I hope I'm wording that so it's understandable. It's clear in my brain!

Basically look at any diagram of any single shaft with a single u-joint at each end and mimic those angles.
If your rear pinion is indeed pointed up, above the centerline of the driveshaft, and the driveshaft is down from the front shaft, then your angles are off.
I honestly don't know how much the front-most joint at the transmission comes into play here, but for just the rear shaft only, it looks off.

Paul

 

I guess what I'm saying is, if for example the centerline of your rear shaft is down 2 degrees from the centerline of your front shaft, then your rear pinion should be pointed down 2 degrees from the centerline of the rear shaft.

Paul

 

And I hope someone will correct me if I'm wrong about this. I don't want to mislead you if I'm off base for this type of install.
What I'm saying is pretty much etched in stone for a single driveshaft, but I really don't know what all changes when you add the second shaft, the carrier bearing and the additional front joint into the mix.

Paul

 

From what I've been reading, I don't think that is right. My rear shaft, for example, is angles down, front high, rear low, 4.5*. My pinion center is tilted up 2* from level to match the downward angle of the mating shaft--yoke higher than pinion center. It makes sense that way. Every vid I watched had the yoke tilting up, pinion lower, because nearly every rear shaft ever made sits lower at the yoke. Right?

I believe all I need to know is if that 2.5* angle where the two shafts join is too much.

 

I don't think 2.5 degrees is too much. But I'm not sure I'm understanding what you said before that.
If your shaft is pointed down in relation to the front shaft, then your pinion should be pointed down too and NOT up. But "up and down" are relative here if we're not talking about the same reference point.

If you're using the ground as the reference, then yes the rear pinion should point upward. But if you're using the driveshaft itself as the reference point (which is what I'm doing), then no, the rear pinion needs to point down.
I'm using the centerline of the rear driveshaft as my reference point, and that's what all of the diagrams and drawings I've ever seen show.

If you're using some reference that shows that it should be pointed above the rear shaft, I'd like to see it. Never seen that before.
And I did not do what I should have during all this. And that is to go out and look at my truck. My '93 SuperCab long bed 2wd has a two-piece shaft setup with carrier bearing. I should be able to see if it's different from what I know about regular single shaft setups.

Too dark now, but if I can I'll go out in the morning and see if the truck is high enough to get any pics.
Getting under even trucks just ain't as easy as it used to be!

Paul

 

I must be explaining it poorly. Every component involved in my driveline--the trans, the small shaft that connects to the trans, the long shaft that connects to the rear end yoke--sit with the end closest to the engine higher than the opposite end. The pinion shaft does too. The yoke is higher, relative to a level ground, than the pinion gear.

 

Measure every angle either off the end of the yoke, or off the u-joint cap that is in the yoke, not the shaft, with the joint pointing straight down. This is critical to get accurate measurements.

If your transmission angle, for an example, is 3.5 deg down, have the first driveshaft around 4 deg down. The u-joint on rear of the first shaft u-joint will match the shaft angle. The reason I say go 1/2 degree more down is so the needle bearings in the u-joint will move around instead of staying in place and wearing ridges into the u-joint if the bearings can't move, which they won't with the joint being perfectly straight in line. Add or remove shims, washers, ect, to get the carrier bearing at the right place to match these angles.

Check the rear axle carrier yoke angle. It should be pointing up toward the carrier bearing at an angle of 3 to 3.5 degrees. This is to account for axle wrap under acceleration. You may need to add shims between the axle and springs to get the correct angle here.

Once you start, don't move the truck until you are finished, for your angle numbers will change according the elevation of where the truck is sitting.

If you do have to stop and restart, recheck all numbers to make sure the axle number you need hasn't changed. On the trans and carrier, the numbers shown may change just because the vehicle is sitting in a different position, but the differences between the numbers won't, if that makes sense to you the way I'm explaining it.

The first driveshaft is an extension of the transmission at the same angle, but with the added u-joint, you need a minimum of an extra 1/2 degree down for proper u-joint operation.

 

The numbers I posted are just for reference. The main thing is the first driveshaft be 1/2 to 1 deg lower than the trans yoke. The rear axle yoke being 1 to 1 1/2 deg lower than the second driveshaft/u-joint angle.

 

Okay. Thanks. So, my trans has a dowward angle of 4*. The shaft that attaches to it has only a 1* slope angle. You're saying that that shaft should have a 4.5* downward slope angle?

Rear end yoke: the rear yoke has a 2* downward slope (yoke higher than pinion gear) and the attaching shaft has a 4.5* downward slope. Are you saying the yoke has to have about 4*?

Once I lower the carrier bearing to get the correct degree of slope/drop, that will decrease the degree of angle/slope in #2 driveshaft. So, the rear end yoke may not need to be adjusted if the final angle degree of the attaching shaft drops from 4.5* to 2.5*, and the yoke has a 2* angle.

 

I think if you drop the carrier bearing so the 1st shaft has a 4.5 to 4.75 degree slope you may be all right. Since the rear yoke is only 2 degrees it should wrap up to the correct angle under load.

If you do end up with a vibration under light throttle at highway speed the rear axle may need a 1 deg shim.

 

The difference between the slope of the shafts and the yokes is the working angle, and your angles are looking fine. What is the most important in your case is the joint/yoke angles of each component being equal.

The rear axle will tilt up under acceleration as the springs flex/wrap. That is why the rear axle yoke will need a lesser angle than the transmission and carrier yokes.

In a perfect world your first shaft would be the same angle as the transmission yoke, but then the u-joint wouldn't work correctly and wear out too soon.

 

Nah, I'm probably the one not explaining it clearly. And yardbird has more detailed knowledge it sounds like.
But I can say that I am not using the ground as my reference in this discussion. My points are all made when using the centerline of the driveshaft as your reference.
With the driveshaft centerline as the basis of all angle references then, if your front yoke is above that centerline, then the rear yoke must be below that centerline an equal amount.
Yes you have pinion climb/axle wrap, so that can be mitigated somewhat with changes, but the bottom line is you want the running angles as close to equal as possible under most conditions.

Here's the basic setup I'm describing (showing just the single shaft, but the reference points are there:

Just think of your intermediate shaft on your truck as the output of the transmission in this diagram.

So regarding the rear shaft only, starting in the rear, having your rear pinion shaft centerline pointed above the centerline of the driveshaft, while the front yoke shaft is also pointed up in relation to the driveshaft centerline, is not workable, at least in a single shaft arrangement. As I've said, I don't know what might change with regard to adding the second shaft and set of u-joints.
That's where yardbird sounds like he's got your back.

Paul

 

I've been researching when I have time, and found this video:
According to him, I should not have more than a .5 degree between the trans and the first driveshaft. I have a 2* angle. I am going to lower the center carrier and see if I can get get the desired/recommended .5*, or less. There should be some splines free on the slip joint to allow the movement.

 

FWIW

https://www.4crawler.com/4x4/CheapTr...line-101.shtml