unjoint, DC and driveline angle threads and links for the noobs? (1 Viewer)

[BlueCruiser84]

Love this video. And the acting is topnotch.

 

[BlueCruiser84]

Another source of vibrations can occur if you do not have enough spline engagement in the slip joint or if the slip joint is worn. Or, and I think more commonly, lifted 80s At 4”+ heights have less spline engagement and are much more finicky about inconsistencies.

I put in 5.29s and suddenly had a nasty rear shaft vibration. The shaft has about 2” of spline engagement (which is borderline acceptable Based on splined shaft thickness) and a bunch of dents, however I had no vibrations before 5.29s and no vibrations with the rear shaft removed after 5.29s. My theory is the small amount of spline engagement is amplifying the vibrations from the dents now that the DS is spinning 600 rpms faster than it ever has before at this lift height.

The shaft needs retubed either way, so I’ll report back with my findings.

 

[BlueCruiser84]

Driveshaft 401 & One-Ton High Angle CV Driveshaft...

www.pirate4x4.com

 

[-Spike-]

Interesting, what your saying here.
I staked slip joint side joint on my front DS on my 80 before taking it to the drive line shop for joints and a balance after 280K miles. They told me it was out of phase, I said it has been in that phase for 280K miles. They insisted it was out of phase and when I got it back they had put it “in phase“.

Now I have a drive line vibration?

Thanks for this info.



devo

Vibes can come from many places, and the original front configuration is only correct at stock height, so if you have a lift all bets are off.

For what it's worth, from the '94 FSM:

 

[landcruiser3DP]

This part is the ujoint. The parts that hold the joint are the yokes.
Untitled by Adam Tolman, on Flickr

thanks. what do i call the part that bolts to the shaft? the non splined yoke? i mean how do i distinguish between the two different types of yokes i guess is what i am asking. <edit: flange yoke which is bolted and sleeve yoke which is not>

 

[landcruiser3DP]

@landcruiser3DP

did you ever get your front DS dents sorted out?



devo

no, i haven’t done anything on it. from the help i got there i guess it is the dust cover which is in fact welded to the shaft?
i’ve been nailing down what to do about caster first i guess. i figure worst comes to worst i have to buy a new dust cover and drop the shaft and run it up to some truck place?
and to figure out if i have an issue i need to get up under there to see if it is binding?

 

[landcruiser3DP]

Vibes can come from many places, and the original front configuration is only correct at stock height, so if you have a lift all bets are off.

For what it's worth, from the '94 FSM:
View attachment 2458009
View attachment 2458021

spike. /thanks/ for these.
i think the front configuration here only applies to the later 80’s. but either way, is there a way to describe this properly in words? do i say the front is out of phase and the rear is in phase? or how would i tell someone to check it? i would say make sure the sleeve yoke on the front driveshaft is 180 degrees out of phase with the - well, with the propeller shaft? and make sure the sleeve yoke in the rear shaft is inserted in line and in phase with the propeller shaft for the rear?

 

[landcruiser3DP]

U joints do not move at a constant speed when there is any angle between the input/output shaft and the driveshaft. They are accelerating and decelerating as the driveshaft rotates. This acceleration/deceleration creates a force ( force = mass times acceleration ). The smaller than angle, the less force is induced into the drivetrain. In order to eliminate the force, the u joints are set up at the same angles, and in phase. The forces cancel each other out.

When the angles are not equal, or the u joints are not in phase, the forces that the u joints are creating do not balance out. This is what causes the vibrations.

Double cardan joints work the same way, except they are designed to guarantee that the u joint angles are identical. So the forces are balanced at the double cardan joint. This requires that the u joint on the other end not be operated at the angle, otherwise it will create forces that cannot be canceled out. This is why the pinion has to be in line with the driveshaft with this type of driveshaft.

hi JP. thanks for this. half the battle is the terms. the other is visualizing it i guess.

when you say there is no angle between the input/output shaft you are saying there is no angular deviation (i.e. they are in line or parallel) between the input shaft driveshaft and between the output shaft driveshaft pair?

and this is because you want one to be going fastest when the other is rotating slowest and vice versa? and in this way the driveshaft does not have any - well any angular moment or whatever i should call it?
also are you saying it does or does not matter if the yokes are aligned or are “180 degrees out of phase”?
i mean it seems like these two issues are totally independent but we are using the term “in phase” for both?

 

[landcruiser3DP]

Driveshaft 401 & One-Ton High Angle CV Driveshaft...

www.pirate4x4.com

thanks. that’s hard core but i will print it and read it...

 

[JeepinPete]

What I was trying to explain in words is so much better explained in the spicer video.

 

[landcruiser3DP]

Love this video. And the acting is topnotch.

great. this is the one i was thinking of.
so he says “non-uniform velocity” occurs when “the angles between the yoke at the transmission and the yoke at the axle are not in proper alignment” or “when the driveshaft is not in phase”. with “in phase” being when the “ears” of the yokes line up.

 

[landcruiser3DP]

What I was trying to explain in words is so much better explained in the spicer video.

both is better. reading it explained in writing by a real person i find almost always is better than videos. makes it much more concrete imho.