I have been drawing up plans for an off-road project, just something to tinker with. But I get a lot of conflicting advice when it comes to driveshaft angles. Help me out if you can:

If I understand correctly, keeping the input (axle) and output (transmission/x-fer case) points of a driveshaft parallel is necessary for controlling driveshaft vibration (not to include the balance of the shaft), or wobble/walking/loping. Is this true?

Now if it is true, then keeping the input/output planes parallel, does it matter if they are in alignment laterally (this may be the wrong term, but from front to rear)? As long as the universal joints cannot reach a point of binding, or where the yokes can come into contact, and the suspension keeps the axle from moving toward/away from the output point more than the available extension/contraction of the shaft, the shaft doesn't care where it's pointing, does that make sense?

Example: transfer case is mounted centerline, front and rear outputs are centerline on the case. There is no "clocking" of the output yokes. Does it matter if the axle's pinion is center, left, or right, so long as the yokes are parallel, and there is no obstruction in the path of the driveshaft? So long as the suspension prevents the axles from moving too much in a forward or aft direction (beyond the extension/contraction capabilites of the slip joint of the shaft)?

When dealing with driveshaft angles, you can get binding by exceeding the operational angle. The yokes don't have to come into contact to bind.
The standard universal joints need to be in alignment, but they also need to be in a similar plane. In other words, you cannot have the output U-joint of the transmission to be significantly highter than the input U-joint at the rear differential.
If this vehicle is lifted, you may want to consider a two piece driveshaft with a constant velocity joint.

What are you building/working with?

When dealing with driveshaft angles, you can get binding by exceeding the operational angle. The yokes don't have to come into contact to bind.
The standard universal joints need to be in alignment, but they also need to be in a similar plane. In other words, you cannot have the output U-joint of the transmission to be significantly highter than the input U-joint at the rear differential.
If this vehicle is lifted, you may want to consider a two piece driveshaft with a constant velocity joint.

What are you building/working with?

Ok, by reading your reply, I think I can now better explain what it is I'm thinking, lol.

Using hypothetical numbers just for discussion purposes, let's say the maximum operating angle of a standard one piece drive shaft with standard universal joints is 45 degrees. If the angle exceeds 45*, the u-joints can no longer transfer the motion and fail (catastrophically, I'm sure).

Given this to be true, does it matter the direction of the angle (up/down/left/right or any diagonal) so long as the angle does not exceed the 45* breaking point, and the input/output yokes stay parallel, at it's furthest possible range of motion (e.g. full axle droop or full compression)?

Does that make more sense?

As far as what I am working with, my questions are based on trying to build something around a datsun transfer case that has both front and rear outputs in centerline below the input. I think this case is a T100L. Not a whole lot of info on it from googling it. What I am wanting to build, is a mild offroad toy that can maintain the lowest possible center of gravity, without sacrificing functional ground clearance. Current plan (always subject to change) will be solid front and rear axles, four link front suspension, three link rear, having the pivot points for the suspension in line with the outputs of the transfer case, so that the shafts and suspension arm will stay as parallel as possible throughout the full allowable range of motion. This will be a low-hp project, by the way, a crawl toy, something to stomp through the backwoods with. VERY low budget.

Sounds like fun. A low-hp, and low budget, crawl toy can be a great deal of fun.
Considering what you want to do, there shouldn't be much problem. If you don't modify the suspension travel, you most likely won't exceed u-joint angle.
BTW, you won't see 45°. And you don't want to! That far exceeds the operating parameter for a standard u-joint.
I say go for it. You'll learn lots by experimenting.
Good luck!

Sounds like fun. A low-hp, and low budget, crawl toy can be a great deal of fun.

Boy, I sure do hope so!

This will be a complete build from the ground up, using existing parts from available donors.

Boy, I sure do hope so!

This will be a complete build from the ground up, using existing parts from available donors.

That makes it a "truck-enstein"... or something like that :rolleyes: