Drive line angle questions

[Richard]

Your current working angles are fine, actually real good. The 3 degree recommendation refers to the working angle of joint not a transmission, driveline or pinion. Your working angles are pretty close to being within 1 degree. Typically the pinion should be down 1-2 degrees to allow for wrap under acceleration.
Unless you have a vibration there is no reason to do anything.

[MySons68C20]

Originally Posted by Richard

Your current working angles are fine, actually real good. The 3 degree recommendation refers to the working angle of joint not a transmission, driveline or pinion. Your working angles are pretty close to being within 1 degree. Typically the pinion should be down 1-2 degrees to allow for wrap under acceleration.
Unless you have a vibration there is no reason to do anything.

So the goal is to keep them within 1 degree of each other correct?

[sfont66]

Originally Posted by Richard

Your current working angles are fine, actually real good. The 3 degree recommendation refers to the working angle of joint not a transmission, driveline or pinion. Your working angles are pretty close to being within 1 degree. Typically the pinion should be down 1-2 degrees to allow for wrap under acceleration.
Unless you have a vibration there is no reason to do anything.

Thanks for your reply
I only have what could be described as a very slight vibration while cruising at 75-80 in 6th gear. It’s possible it’s not even drivetrain related. I haven’t driven the truck for 5 months now(winter weather) and it will be another month or two before I can do so again, to investigate further.

[samert111]

I always understood that the trans output shaft centerline and pinion centerlines should be parallel to one another but not necessarily inline with one another to improve ujoint wear. The centerline to centerline difference to create a max 3° driveshaft angle.

[Richard]

Originally Posted by samert111

I always understood that the trans output shaft centerline and pinion centerlines should be parallel to one another but not necessarily inline with one another to improve ujoint wear. The centerline to centerline difference to create a max 3° driveshaft angle.

3 degrees references the operating angle of the ujoint, not a component. The components create the operating angle. Operating angle is what is important. Understand, it is not like the ujoint explodes if that number is exceeded. It is said the life of joint is decreased if above 3 degrees. I have had two previous 4x4's and my current one. Past two and current had and will exceed that 3 degree theshold. Never had a problem with ujoint life or excessive vibrations. My current build will have about a 15 degree driveshaft angle at ride height and 25+ degrees at full droop. It will give me about 5 degrees operating angle on the joints in the double cardan cv at ride height. Will live a long service life. The operating angles constantly change while driving with any suspension. Need to get them close at ride height. IMO many people over think this.

[MySons68C20]

Originally Posted by Richard

3 degrees references the operating angle of the ujoint, not a component. The components create the operating angle. Operating angle is what is important. Understand, it is not like the ujoint explodes if that number is exceeded. It is said the life of joint is decreased if above 3 degrees. I have had two previous 4x4's and my current one. Past two and current had and will exceed that 3 degree theshold. Never had a problem with ujoint life or excessive vibrations. My current build will have about a 15 degree driveshaft angle at ride height and 25+ degrees at full droop. It will give me about 5 degrees operating angle on the joints in the double cardan cv at ride height. Will live a long service life. The operating angles constantly change while driving with any suspension. Need to get them close at ride height. IMO many people over think this.

Great post!!^^^^^^

[2500HD]

Originally Posted by Richard

3 degrees references the operating angle of the ujoint, not a component. The components create the operating angle. Operating angle is what is important. Understand, it is not like the ujoint explodes if that number is exceeded. It is said the life of joint is decreased if above 3 degrees. I have had two previous 4x4's and my current one. Past two and current had and will exceed that 3 degree theshold. Never had a problem with ujoint life or excessive vibrations. My current build will have about a 15 degree driveshaft angle at ride height and 25+ degrees at full droop. It will give me about 5 degrees operating angle on the joints in the double cardan cv at ride height. Will live a long service life. The operating angles constantly change while driving with any suspension. Need to get them close at ride height. IMO many people over think this.

i agree with you and i think we are saying the same thing. if the componets are correct so will the ujoint operating angle. the one thing we may not agree on is what excessive vibration is. In my opinion any driveline vibration is excessive. Unless a vehicle has a big lift there is no reason the component angles and therefore the oprtating angles cant be really close. I just went though this on my truck and as it turned out the brake drums were causing the vibration.

[Richard]

Originally Posted by 2500HD

i agree with you and i think we are saying the same thing. if the componets are correct so will the ujoint operating angle. the one thing we may not agree on is what excessive vibration is. In my opinion any driveline vibration is excessive. Unless a vehicle has a big lift there is no reason the component angles and therefore the oprtating angles cant be really close. I just went though this on my truck and as it turned out the brake drums were causing the vibration.

Regarding component angles, saying that my engine/trans, drive shaft or pinion should be at a certain angle is really useless info IMO. Those optimum angles are going to be different for my dropped truck, lifted truck or stock truck. I will adjust those angles to obtain the best ujoint operating angles for the vehicle.

I do not recall stating it was okay for the operating angles to be far apart. Infact, I said they should be within 1 degree. I did point out that exceeding the 3 degree recommendation is not a big deal. I have a 94 extended cab that I installed a 6/8 drop on and drove it that way for many years. Is lifted now. Has a two piece drive line so I have dealt with that as well for experience.

I also said the operating angles constantly change. Depending on suspension type such as the trailing arm and angled leaf springs on the old trucks the pinion angles down the more suspension compresses. A 4 link may be more linear depending on link bar length. Then there is wrap from torque. Which still exists even on a trailing arm truck or even a 4 link.

All is good with me, just wanted to explain where I am coming from. My last comment about overthinking it was not meant as an insult. I just believe that searching for the perfect combination of angles can be a fruitless endeavor. It is literally impossible to keep the ujoints in phase under all driving conditions.

[2500HD]

Originally Posted by Richard

Regarding component angles, saying that my engine/trans, drive shaft or pinion should be at a certain angle is really useless info IMO. Those optimum angles are going to be different for my dropped truck, lifted truck or stock truck. I will adjust those angles to obtain the best ujoint operating angles for the vehicle.

I do not recall stating it was okay for the operating angles to be far apart. Infact, I said they should be within 1 degree. I did point out that exceeding the 3 degree recommendation is not a big deal. I have a 94 extended cab that I installed a 6/8 drop on and drove it that way for many years. Is lifted now. Has a two piece drive line so I have dealt with that as well for experience.

I also said the operating angles constantly change. Depending on suspension type such as the trailing arm and angled leaf springs on the old trucks the pinion angles down the more suspension compresses. A 4 link may be more linear depending on link bar length. Then there is wrap from torque. Which still exists even on a trailing arm truck or even a 4 link.

All is good with me, just wanted to explain where I am coming from. My last comment about overthinking it was not meant as an insult. I just believe that searching for the perfect combination of angles can be a fruitless endeavor. It is literally impossible to keep the ujoints in phase under all driving conditions.

Whatever. live with your "good enough" result. You contradict yourself mutiple times and i will not argue with generalities. i am out.

The fact the engine/trans angle should be 3 degrees or less due to oiling and fueling issues is hardly usless. You should have a 3 degree or less engine/trans angle regatdless of lifted or lowered.

You never mentioned the angles on your lifted or lowered 94. do you even know what they were. Did it vibrate? Vibrate acceptable to you? acceptable to me? I doubt it.

Recomendations, why would anyone listen to the manufactures recomendations? Richard from SoCal seems to be much smarter. Run u joints from 1 degree to 90 degrees and they should be good..... i think. ask Richard to be sure.

I agree angles constanly change but they are at max droop or max compression for milliseconds if ever. The suspension stays within 2 degrees 98% of the time for a street driven truck.