Driveline angles????

[bill69f100]

So I thought it would be cool to go get a 05' CV police interceptor and put the motor and trans in my 69'. Well sofar after 6 months I was able to drive it. Welllll it's pretty quik without the bed on it. The problem is the 15 to 30 mph vibration is a pain. I took it to a diveline place and they told me the angles are all off. I checked the rear and have 6 deg. on the 9" diff. The 2nd driveline is 10 deg.(as you look from the front of the truck) The carrier is new and seems o.k. The 1st driveline I put at 1 deg. The tail shaft I have at 5 deg. I was told the difference between the trans and the diff should be 1-2 degrees. The two drivelines should be .5 to 1.5 degrees. Does anyone know what the degrees on 2nd driveline is from the factory??? On that the degrees on the 2nd. Someone told me to measure twice and cut once. I cut and didn't measure.

[averagef250]

What's the reference surface? What tool did you use to measure the angles?

When I do 2 piece shafts I run the transmission side shaft within a degree of the engine/transmission angle and match the pinion angle to the angle of the forward driveshaft or engine/transmission. The pinion angle and engine/transmission/forward driveshaft angle should all be within a degree of one another.

The issue with two piece shafts is there are three U-joints. The cyclic accelerations from each joint require another joint operating at a complimentary angle to cancel out those accelerations. When you have three joints you have an odd duck out joint. Any accelerations made by that joint will be be felt when the vehicle drives so it needs to be as straight as possible as to not cause them.

If you cannot achieve one straight (within a degree) joint with the other two complimenting one another then the odd duck joint needs to be a CV (double cardin) style joint instead of a standard U-joint.

From your measurements it sounds as if you lower the carrier to get the forward shaft angle to match the engine/transmission you should be OK.

However, as a general guideline you want to err on the side of the pinion being lower rather than too high. Pinions lift up under load, especially under light pickups.

[bill69f100]

I used the pads on the pinion shaft on the diff. Then I used the slip yoke pad on the tranny end. I have a $20 protractor that I'm using. So if I got it the 1st and the 2nd driveline have to also be within 1 deg of each other. The carrier would seem to sit lower than the tranny????

[70_F100]

One important point to remember, you need at least a small angle at each U-joint.

[averagef250]

One important point to remember, you need at least a small angle at each U-joint.

You have to be careful how you give this advice to people, especially those that may not fully see how U-joints work and why the angles they operate at are important.

You aren't going to get a U-joint to operate without angle, in a vehicle in operation. Everything moves around too much. U-joint cyclic accelerations increase exponentially with operating angle. That understood you want a U-joint that doesn't have a match in a multiple joint system to have as minimal an angle as possible; less than a degree.

[bill69f100]

The protractor I used I got from the driveline shop here in town. Yes it is plastic. I have the truck sitting "naturally" as it would drive down the road. I'm going to double check the degree at the carrier's crossmember in the center. The way you explained it makes more sense. It looks like I'm on the right track. I'm taking tomrrow off from it. Friday I'm going to hit it again. I'll let you know what I come up with.

[bill69f100]

My pinion is 6 deg., trans yoke 5 deg., mounting plate for carrier bearing is 3 deg., bottom of carrier is 3 deg.. Tranny side 1st driveline 1 deg., output of carrier is 1 deg., top of 2nd driveline 10 deg., bottom of 2nd driveline 10.5 deg.. I used a Johnson Magnetic Angle Locator.(don't know if I'm allowed to give manufacture names. sorry) I also see that my tranny cross member needs to be lowered a little bit. Thanks for helping.

[averagef250]

My pinion is 6 deg., trans yoke 5 deg., mounting plate for carrier bearing is 3 deg., bottom of carrier is 3 deg.. Tranny side 1st driveline 1 deg., output of carrier is 1 deg., top of 2nd driveline 10 deg., bottom of 2nd driveline 10.5 deg.. I used a Johnson Magnetic Angle Locator.(don't know if I'm allowed to give manufacture names. sorry) I also see that my tranny cross member needs to be lowered a little bit. Thanks for helping.

OK, if these angles are pretty accurate in relationship to one another, your pinion is 6 degrees, the angle the rear shaft sits at is about 10 degrees, the angle the front shaft sits at is 1 degree and the engine is at 5 degrees. None of the other stuff matters, but it sure would be nice to know the angle the frame was at when you measured this stuff unless you don't plan on moving the truck until you have this stuff fixed.

As I wrote previously it looks as if you need to lower the carrier bearing so the front shaft is around 5.5 degrees instead of 1 degree as it sits right now.

Take the carrier bearing bolts out, put a floor jack under the carrier bearing and lower it until you have the front shaft about 5.5 degrees. Measure the distance between carrier bearing and mount, fabricate spacer for the carrier bearing. Tip- If you are unsure you got everything right instead of making a steel or aluminum spacer right away just make it out of wood. Drive the truck, make sure everything feels right, then make one from metal.

[averagef250]

Why are there posts missing from this thread?

[bill69f100]

I got the angles done. I have a 20 mph +-2 mph. It's alot better than before. I did however, noticed the carrier and the tranny tail shaft are not parallel. Had a few choice words in there. I measured them and found the offset to 7/8". The engine/transmittion is 16 1/4" and the carrier is 15 3/8" to the outside of the frame on the passenger side. I think that may be part of my problem too.