Drive shaft angles.
 

So what do we know about angles?

I thought I was good with my set up.

Pretty close to perfect vertically
https://i.imgur.com/nAjIKMc.jpg
https://i.imgur.com/OkvRnsF.jpg

Got my drive shaft today and then I noticed this

https://i.imgur.com/LQ128SV.jpg
https://i.imgur.com/gjEBVfw.jpg

My diff pinion is offset to the passenger side.

I’m thinking as long as it’s horizontally parallel as it is vertically then I should be good?

How do you measure horizontally?

And what about the other axis’s?

can you put a glob of play doe in the middle of the flange then insert a laser pointer and find your zero,... you'll also see where you sit horizontally, vertically and see if its on an angle "yaw"

Your way over thinking this.
Does it bolt on easy? Did you have to hammer it in?
Have you drove it?
That aside how would you actually measure your axis? Are you going to shim the tranny and the diff to be centered? How would you even measure center line parallel to tranny to diff?

Or would you just trust the company that made you solid driveshaft to perform as advertised?

There is nothing wrong with the driveshaft.

I installed a custom diff, custom transmission and all the custom mounting hardware. I’m trying to make sure I’ve got it all right and not put unwanted stress on any of the components.

I’m sure it will work fine. But I’m not sure that my horizontal angles are parallel...and I want it all to work perfectly. Bouncing it off the community here to get some input.

The transmission can be adjusted a little bit, the diff would be a bit tricky to move if needed. So yes, the question is how do you measure the horizontal angles?

I’m not following.

You've bolted a lot of hardware up. My recommendation is to loosen (a couple turns,) the diff and carrier and see how much L/R play you have. I think a tiny bit can help you straighten it out and make it perfect.

You mean slide it towards the driver side? The Ford 8.8 pinion is offset is quite a bit more (1.5”?) than any play I’d have in the bolts...

I have solid bushings in the subframe to body and solid bushings mounting the diff to the subframe. The holes are not ovaled like the factory bushings and all of it was tough to install because there was very little play in the bolts.

In other words...if I loosen the diff and subframe and try to shift it over it would only move 1/4” max...if that...not enough to straighten the shaft but maybe enough to horizontally rotate the diff to get the correct angle.

Lots of cars were designed with offset differentials and angled driveshafts. I think having an angle is okay. From everything I read though, they have to be parallel.

I would agree. Put a laser on the diff yoke facing forward and then on the trans yoke facing rearward. The lines should be parallel.

I agree with the suggestion from @gtpvette

I think 1/4" is a pretty big difference as far as straightening out the 1.5" gap, that's a 16% improvement.

Again, I think some is fine, but I would do what I can to minimize it. The straighter the joint, the stronger.

Ah......
Well now. Easiest way would be a small laser pointer in a custom holder that would fit in the drive shaft hole on the tranny side.
If you know someone with a lathe he could make something up.

thats what I tried to say put some play-doh on the end of the yoke and insert the laser pointer,... put a cardboard template couple feet away and spin the yoke to centre out the laser,... then reference it to your tranny or diff.

Well okay then...let’s say I put a laser pointer in the hole in the back of the transmission output shaft...I’ll have a red dot on the front of my gas tank.

Put another laser at the center of the pinion shaft on he diff...I’ll have a red dot on the bottom of the transmission crossmember.

What do I do with this data from here?

In the mean time...I took a laser level for hanging pictures, squared up the yokes and scratched a 4 foot line on the ground below the diff and trans. Measured the same distance at either end.
https://i.imgur.com/sfbO4GV.jpg
https://i.imgur.com/SgbVCzl.jpg
https://i.imgur.com/oN7MXVq.jpg

Then I did the same thing with the laser level flat on the flange and the output shaft...scratched 6 foot parallel lines. It was 1/2” apart at either end.
https://i.imgur.com/ifUWMiJ.jpg
https://i.imgur.com/DhBRuHL.jpg

I’m gonna say the trans and diff are parallel on the horizontal plane...anyone gots better idea?

Still looking for a better way to measure this...help me understand the laser pointer idea.

Ok the lazer pointer has to be a pen style one. One thats used for presentation and stuff. Not a lazer leveler. You know the kind kids would always get.

When you put in the tranny shaft, assuming it's in a round holder type. It should pretty much be centered that should point in a straight line.

As to mock up a fixture, the simplest way I can think of that doesn't require complex stuff is a standard 30mm socket and glue on the lazer pointer to it. Just square it before the glue dries. That should be some what reliable.

Another way, go to the local hardware store pick up a 6' or longer rod that's straight enough and that would fit into the shaft. Then just use the leveler just to make sure it's nice and flat. You may need a thrid or forth hand and something to keep the rod level that should give you a physical straight line.

Or get a 1/2" rod to fit in the 1/2" 30mm socket that would fit in the tranny. And level it and what nots. Just don't use a impact socket, that's too thick and won't fit.

guys stop overthinking this,... use play doe to hold the laser on the yoke. put a cardboard template a couple feed away. spin the yoke and move the laser until the dot on the cardboard isnt moving... thats how you know the laser is centered on the yoke. then go see where the laser is pointing and will give you the indication of where the alignment is.