drive line angle

[miked]

Hello
I am converting from e4od to zf5 in my 1994 f250 idit

short story.
I have a 1990 cross member from a 1990 zf5 which would have been perfect but is rusted too badly to use.
Found an L shaped cross member in my parts stash which matched the frame bolt face to tranny mount bolt face off set that matches the height offset on the 1990 cross member.
One side bolts to the outside of the frame.

The zf5 cross member has a greater off set between the 2 faces (frame to tranny mount) than the e40d cross member,

The transmission is in, with the L shaped member clamped in place ready to drill matching boltholes in the frame and the drive shaft with hanger bearing is also installed, which when I looked at it made me decide to check my drive angles.

What I found

The face of the transfer case yoke, and the face of the rear end yoke, are less than 1/2 degree out to each other.
So centre line angle of the engine-transmission and centre line of the axle yoke are on the same axis.
I am asuming that the transfer case yoke is in line with the trany center line.

The drive shaft spline is 5 degrees out to the yoke faces and needs to move downward to correct this.
Using trig, I calculated that I need a 2.45 inch spacer under the hanger bearing to correct the 5 degrees.
I will make this spacer and recheck the angles.

My concern is why I am having to do this ???
Am I missing something?
any insight would be appercated.

Thanks

 

[u2slow]

IMHO, too fussy about the driveshaft angle IMHO. The factory wasn't that perfect. Try it as-is.

 

[Isaac Ristow]

I have always been told the shaft ahead of the hanger needs to be at same degree as the engine/trans. I have a inclinometer app on my phone I put my phone sideways against the oil pan or transmission pan get the degree then space the hanger bearing to get that same degree on the front half of the shaft as the degree of the power plant. The rear most shaft is responsible for flexing to make the difference in height/ suspension movement

 

[DaveBen]

This is why they make angled shims for the differential. You can change the angle of the yoke to sorta match the tranny output shaft.

 

[miked]

5 degrees just seemed like too much.
If it had been less than 2 degrees, I might have tried it as is.
It is the size of the spacer I calculated that kind of shocked me. I did not think ford would be that far out on their engineering.
I still have to make it and verify my calculation though. But I am petty sure it will not be far off, just looking at it visually.

Every thing I checked shows that the engine /tranny angle matches the axle angle, and tapered shims will not fix this.
Unless, the angle of the U joint on the first drive shaft, which does not work against another U joint, is not important, then tapered shims would work to fix this.

Does this make sense.

 

[Black dawg]

First section of shaft angle should match engine trans t case. Pretend it is just an extension of the t case. Pinion angle should match engine and first section of shaft.
By the book, you want that first u joint running through a small angle, less than .5 though, to at least move the rollers.
The un molested trucks that I have measured had zero angle on that first joint. This is crew cabs. I have seen some supercab trucks with angles that shouldnt work but are fine?

 

[miked]

Thanks all
I suspended the hanger bearing by longer bolts, and a 2 1/4 inch gap gave me matching angles.
This is the super cab, so maybe this is normal.
It may look weird, but I think I will space the hanger bearing to bring the angles closer together.

 

[u2slow]

Thanks all
I suspended the hanger bearing by longer bolts, and a 2 1/4 inch gap gave me matching angles.
This is the super cab, so maybe this is normal.
It may look weird, but I think I will space the hanger bearing to bring the angles closer together.

Turns out my truck uses a piece of u-channel to space down the bearing.

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[miked]

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[miked]

Found these specs.
They are based off of the bottom of the frame rail just behind the cab.

Looks like an angle change of .9 degrees at the tail of the transmission to front drive shaft, and a 1.9 degree différance between the 2 u joints on the back drive shaft with an 8.3 degree or a 7.6 degree angle on the rear drive shaft depending on what spring pack you have.
Maybe the rear drive shaft différance between the 2 U joints is a way to adjust for loading or axle torque.

I wonder if that centre channel may change between 4x4 and 2wd as I am putting in a 4x4 tranny into a 2wd

Regardless, I have some more measuring to do

 

[miked]

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[miked]

Thanks u2slow your picture clued me in.
I just checked my parts truck and that hanger bearing bracket is a good 2 inches deeper than the one on my truck.
So any one converting from 2wd to 4x4 needs to nab that bracket also.

 

[u2slow]

Thanks u2slow your picture clued me in.

Not even 5 mins after that pic, I thought to check my 2wd for comparison. Promptly slipped on the wet driveway and broke my collarbone! What a day...

 

[miked]

I am sorry hear that happened to you while trying to help me out.

 

[u2slow]

Definitely not your fault!

Ridiculous stuff happens sometimes