Pinion angle - let's hear from the "experts" only.

[Ramsey_ElWardani]

I’d like to hear from those of you that have experience setting the Pinion Angle on a Four Link truck. I have my opinions, based on many years of experience, but am always willing to get edumacated by those with experience and knowledge.

Travel is 30” from full bump to full droop.
Transmission output shaft is pointed down at 6 degrees.
One piece driveshaft with U-joints.

What do you think is optimal pinion angle at full bump?
What do you think is optimal pinion angle at ride height?
What do you think is acceptable pinion angle at full droop?
What do you think is optimal pinion angle change over full cycle?
Describe what you think is an optimal pinion angle curve through its cycle.

I appreciate hearing what those in the know think.

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[partybarge_pilot]

Set it to match the tranny at ride height and check for bind at bump and droop.

The curve is directly related to the amount of squat built into the rear and will be different for each vehicle. Not a whole lot you can do about it after it's built..........

[bigtex]

Set it to match the tranny at ride height and check for bind at bump and droop.

The curve is directly related to the amount of squat built into the rear and will be different for each vehicle. Not a whole lot you can do about it after it's built..........

Thats what I have also done with all mine, set it at ride height to match the trans. and check for binding

[SROWE]

I wish my trans was pointing down at 6 degres,with the other guys match pinon to trans angle,anyone checked out highangle driveline new 48deg cv joint ,what do you guys think about that thing i am a little worried about all the wieght but would love to have a rumble free truck if i have a full tank or not.

[Ramsey_ElWardani]

Set it to match the tranny at ride height ...

So if the transmission is down 6*, set the pinion pointing down 6*, or is it up 6* so that the two center lines are parallel - just to be clear on what you are saying? I am assuming you meant the latter.

How much would you let the pinion angle roll up at full droop?

[partybarge_pilot]

Parallel.

Rotation, thats a guessing game without knowing a lot more details.........

[SROWE]

You would need to point the pinion 6 deg up to match them.

[bigtex]

So if the transmission is down 6*, set the pinion pointing down 6*, or is it up 6* so that the two center lines are parallel - just to be clear on what you are saying? I am assuming you meant the latter.

How much would you let the pinion angle roll up at full droop?

To match trans at ride height your rear end would be up 6 degrees. Sorry did not read the whole thing I'm not an expert but this is how I have done it on many linked trucks.

[FABRICATOR]

I'm no expert, but there is some basic information missing here. What about the rest of the truck? What is it used for?

[Ramsey_ElWardani]

Well we seem to have some consensus, at least at ride height; and it is consistent with conventional thought in the Driveline industry.

When a U-joint is run at an angle the drive shaft will actually speed up and slow down twice during each revolution, due to the changing angular velocity of the U-joint ends. When there is a U-joint at each end of the drive shaft and they are run at different angles, a vibration will result from unequal velocities at the opposite ends of the drive shaft. There will be no vibration if the angles are the same at both ends of the drive shaft because both ends will speed up and slow down at the same time and in the same amounts. If the angles are off the U-joints will still cause the speed to change at the same time (unless the drive shaft is twisting) but in different amounts, causing vibration. Keeping the pinion parallel with the output of the transfer case will keep the angles the same, avoiding vibrations.