Drive Shaft Vibrations Solved Step-by-Step

Hi All, Hoping for some advice on correcting drive shaft vibes. Recently put a Dakar leaf spring in (medium load) along with OME struts and springs up front. Also installed OME carrier bearing spacer kit.

Within a month or two, I noticed that my rear u joint failed (squeaking quite prominently) and was creating a vibration around 80-90km/h. I removed the driveline, and replaced 2 of the 3 u joints and carrier bearing while I had it out, indexing all contact points to ensure everything stayed aligned. Put everything back together. Squealing gone, but vibrations remained.

Got an alignment done, tires rebalanced at the same time, but the vibration remained. No sign of a bad wheel bearing (no play) and nothing in the driveline has any slop.

After spending a good amount of time reading through the forum, particularly this thread, I believe it's a rear diff pinion angle issue. I went ahead and measured angles. Using the flat metal bar from a combination square as a flat surface, i zero'd out an inclinometer on the transfer case pinion flange, and from there got a reading of 4.9 degrees on the front shaft, a reading of 5.2 degrees on the rear shaft and a reading of 3.9 degrees on the rear diff pinion flange. This means a working angle between transfer case and front shaft of 4.9 degrees, a working angle between front and rear shaft of 0.3 degrees, a working angle between rear shaft and rear diff of 1.4 degrees and a difference between transfer case and rear diff of 3.9.

If I'm understanding everything correctly, in theory, a 4 (3.9) degree pinion shim would resolve my vibration. Is this correct? I've attached an image with my readings to be as clear as possible. To confirm, my numbers are all based off the transfer case pinion reading 0* on the inclinometer. Thanks in advance!

 

What does this vibration feel like to most people? Is it like a high speed vibration, or more low speed, like a rythmic shaking,?

What frequency do you guys see? Imagine a salt shaker, very slow vibration. Or faster, like a washing machine on spin cycle? Or much faster, like driving over rumble strip?

 

Can't speak for others but mine are more like a washing machine on spin cycle.

 

Howdy all, at my wit's end with this and about to mag dump the parts shotgun.


I got vibes I can't seem to fix and I'm not even sure what I have and haven't tried anymore I've fought wit it so much so trying to start from scratch now and hoping you all can help as I have spent days reading and I'm more confused than ever, there's so much misinformation and random things that work for some and make things worse for others.

So here's my measurements following the below methodology;



Zero'ing at the TC bolt holes surface my first shaft angle is 6.5°, then I have 11mm drop on the carrier bearing, second shaft is 6.8° so my 2 shafts are inline, I then zero'ed the gauge on 2nd shaft and got 4.8° pinion up on the rear axle. (2° in relation to the TC when not zero'ed on 2nd shaft.)

Compared to the angles I got when zero'ing my Johnson Level Inclinometer off the shop floor I have these angles:

TC flange 1.5° down, 1st shaft 8.1°, 2nd shaft 8.1° pinion flange 3° up meaning the TC and Diff flanges are within 1.5° of each other at rest, under load the axle would rotate and climb and I assume that's where my vibes are so in theory I need to further angle shim my diff down?

I currently have 1° shims to point diff pinion down and 4° shims on my bench if I swap those out it should put my diff at 0° down, and under driven torque load it should be within tolerance of parallel to the TC's 1.5° down yes?

Right now I get real bad vibes coming on around 60mph that get worse and worse the faster I go and they seem to get worse in general when coasting (diff no longer rotated up which would support alignment method #2 in my understanding meaning diff down would be a bad thing which contradicts conventional alignment understanding) or when I have an empty gas tank.

The other method #2 I'm considering trying is removing the carrier drop and putting the 4° shims skinny end forwards to align the diff pinion up towards the rear shaft as that seems to solve it for most folks that I have read but in my understanding that would make the middle u joint unpaired or uncanceled and thus vibes but most people say no?

Also in my research they use 3° shims to do the above method #2 but I'm lifted a little more than most in the rear, alternatively I can stack my 1° opposed to my 4° for a 3° angle but my measurements imply 4° pinion down should parallel my TC and Diff flanges as Badger has said Toyota intended.


Only other details I can provide is:

Truck weighs close to 6k lbs, all steel bumpers, sliders, sids, winch, shell, lots of gear, full matching spare etc...

285/75/17 E Load Cooper ST Maxx tires (34's)

Stock gears, manual transmission

3" lift in front, appropriately 4" in rear, Dakar HD gen 2 springs with an extra leaf added, Archive Garage Hammer Hangers with high clear cross tube.


Thanks for your time.

The best profile picture I have right now of the paint shaker herself to show the lift heights front/rear showing I have a bit of rake.



I'm starting to think I have a bad driveshaft and all this is moot as I can make the vibes worse but just can't seem to fix them, just hoping I'm missing something.

 

Good news: your data is consistent between both sets of measurements, so the values you already have can probably be used to correct the problem.
Bad news: your angles are waaay off, and really need to be corrected.

Taking your numbers and plugging them into my calc sheet:

... here's what I'm getting. Correct me if I'm wrong.

theta_1 - transfer case flange
- Data set 1 (zeroed on TC): 0.0 degrees
- Data set 2 (zeroed on floor): 1.5 degrees

theta_2 - forward half of driveshaft
- Data set 1 (zeroed on TC): 6.5 degrees
- Data set 2 (zeroed on floor): 8.1 degrees

theta_3 - rear half of driveshaft
- Data set 1 (zeroed on TC): 6.8 degrees
- Data set 2 (zeroed on floor): 8.1 degrees

theta_4 - rear diff flange
- Data set 1 (zeroed on TC): 6.8 degrees - 4.8 degrees = 2.0 degrees
- Data set 2 (zeroed on floor): 3.0 degrees

Using these measurements, you get the following u-joint working angle values.

delta_1 = | theta_1 - theta_2 | (transfer case u-joint working angle)
- Acceptable value: =< 0.5 degrees
- Data set 1: | 0.0 - 6.5 | = 6.5 degrees
- Data set 2: | 1.5 - 8.1 | = 6.6 degrees

delta_2 = | theta_2 - theta_3 | (center u-joint working angle)
- Acceptable value: delta_3 +/- 0.5 degrees, and no greater than 3.0 degrees
- Data set 1: | 6.5 - 6.8 | = 0.3 degrees
- Data set 2: | 8.1 - 8.1 | = 0.0 degrees

delta_3 = | theta_3 - theta_4 | (rear diff u-joint working angle)
- Acceptable value: delta_2 +/- 0.5 degrees, and no greater than 3.0 degrees
- Data set 1: | 6.8 - 2.0 | = 4.8 degrees
- Data set 2: | 8.1 - 3.0 | = 5.1 degrees

delta_dev = theta_2 - theta_4 (difference between forward half of driveshaft and rear diff flange alignment)
- Acceptable value: ~ 0 degrees
- Data set 1: 6.5 - 2.0 = 4.5 degrees
- Data set 2: 8.1 - 3.0 = 5.1 degrees

As far as your next step goes... I'm not sure. I would personally remove the carrier bearing drop kit to try and get delta_1 (transfer case u-joint working angle) lower. Hell, flip the carrier bearing if removing the drop kit doesn't do enough.

Once that's done, then it makes sense to shim the rear diff to reduce delta_dev (rear diff flange matches the new angle of the front half of the driveshaft). Retake measurements and see where that leaves you?

*Edited to add*
While the above steps will probably get you going in the right direction, it might not fully correct the problem. With the amount of rear lift you have, it's possible that delta_2 and delta_3 (center and rear u-joint working angles) will both exceed the 3.0 degree maximum working angle value specified by Spicer. The vibrations may go away, but those two u-joints may be susceptible to accelerated wear.

 

Agree with above. 6.5 degree at transfer case joint is too high. Remove the carrier bearing shim to reduce the angle and then measure angles to get a baseline. Then shim center bearing up or down (flip carrier bearing if necessary) to get angle across the transfer case Ujoint to be equal or near equal to angle across the Ujoint at the carrier bearing. Once that is done, you can chose a axle shim to reduce angle across the differential Ujoint to be close to 1 degree. Fun part is any change in axle shim angle will change the angle across the carrier bearing so go back and check and readjust shims at center bearing to get back to equal angles across first 2 Ujoints. Don’t overlook side to side angle anytime you shim the center bearing as it can move off center when adding shims; if it is not in a straight line between the transfer case and differential Ujoints then it will may contribute to vibrations.

 

Thank you so much for your time and help, I'll buy you a beer if we can fix this.

I believe what you've detailed confirms what I was beginning to consider and parse out last night; if I'm understanding correctly.

As a very hands on and visual learner I have provided some quick sketches below:

My current configuration cardboard sketch somewhat exaggerated to further convey direction of flange tilt.




I have been so focused on getting the TC and Diff flanges parallel and the first and second shafts inline with each other I was disregarding the assembly as a whole, specifically the flange to shaft angles which is if I understand you correctly why I have vibes even with it setup conventionally correct?

Disregard the 27.2 and 41.9 those are approximate tape measure measurements from middle side of TC flange to center cap of U joint and from center cap of U joint to middle of diff flange drive shaft measurements.

So I need to go from:




Where 1 and 2 are parallel and should cancel and 3 and 4 are inline thus nothing to cancel out to:




That would reduce the shaft to flange angles but I'm now confused as to how that wouldn't cause vibes being that there's no two points that are equal and opposite to cancel out, shouldn't that generate standing waves as everything is operating at a unique angle?

As for the accelerated wear I don't really care right now as it can't accelerate wear anymore than jiggling like a paint shaker down the road does on everything including my sanity.

Last night I crawled under a friend's 3/3 lifted 3rd gen and while he was on a Rough Country block/spacer lift the rear blocks were tapered to point the diff flange up and he had a 5/16 carrier bearing drop and claims no smooth as glass at 80mph which further supports and confirms the theory and what I believe I need to do.



Found some pictures that may or may not help:

I currently have 1/8" washers stacked to a 1/2" carrier drop so I'll try going to a 5/16" drop using different washers



And my current leafs with the 1° shims "fat" end forward.



So I need to reduce my carrier drop to improve the TC to 1st shaft U joint angle and then install my 4° axle shims to point pinion up to reduce 2nd shaft to diff pinion angle and check and adjust from there, does that sound right?

Is 4° too much or not enough? I can stack the 1° opposite or the same to make a 3° or 5° if necessary.


Last question, I'm 90% positive I put everything back in phase when I replaced my carrier bearing and middle U joint as all my zerks are perfectly inline as far as I can tell and the angles using a straight edge and the Inclinometer off the side of the U joint caps say the angles are within measurement tolerance but just in case how many splines are on the middle yoke and slip yoke so I can figure out if it is off by a single tooth or something based off degrees?

IIRC I thought the center yoke and slip yoke were keyed so they could only slide back in one way but I may be wrong?

Again I really appreciate your time.

 

Its a common misconception that the angles must be in opposite directions with input and output shafts parallel. As long as the two angle are equal, they should cancel out.

You may also want to check your center bearing, looks like the rubber portion is beat up.

The Rodding Roundtable - Driveline Angles Explained

 

Interesting, thank you!

As for the center support it's gravy, what you're seeing is the Sikaflex from doing the "urethane injection reinforcement mod" or whatever it's called.

I just replaced that center support a year ago with new OEM.

 

Answers to your questions:

You're on the right track, with one exception. You want to align the rear diff flange (2) and front driveshaft (3) so they sit at, or close to, the same angle.

I would yank all carrier support bearing spacers and use that measurement as a baseline. You really want the TC flange and front half of the driveshaft to be in line, or as close as possible. Getting less than 0.5 degrees working angle for the foremost u-joint is unlikely, so don't sweat getting it absolutely perfect. For reference, my truck (DCLB) came stock at ~2 degrees here.

Yep, that's my recommendation.

That completely depends on what your measurements tell you, after you remove the carrier bearing drop.

I honestly have no idea. I can figure out some of the science behind this stuff, but I have almost no experience with the actual hardware. I'm sure some other, more experienced TW folk can give you some pointers here.

*Edited to add*

I sketched up a quick illustration to show what I'm talking about.



Basically, everything is in line except for the rear shaft. That's the desired end state, and it *should* fix the problem. Whether the rear two u-joints are at or below a 3 degree working angle is another matter entirely, but let's get the vibes fixed before we worry about that.

Disclaimer: I'm not an expert on any of this stuff. I did a ton of research into this topic before getting my own lift installed a couple years ago, but that doesn't make me an authority on driveline dynamics. If I'm putting out bad information, someone please correct me.

 

@Key-Rei, did you ever get your vibrations figured out?

 

Not precisely.

I have come to the conclusion shit's fucked and I'm getting a custom driveshaft with a double cardan after the carrier made, I go see the shop in two weeks.

Nothing I have changed has done much more than change at which speeds the vibes are felt the worst and irregardless of any changes made it still feels like the shuttle on reentry above 65mph.

 

My buddies brand new 22 f150 has the same slight take off jiggle my Tacoma has(5-10mph). I honestly believe most these vibe issues will never be cured even with the best angles. My Tacoma has had this take off jiggle since new.

 

I can't speak for your buddies f-150, but typically on the Tacoma low speed take off jitters are due to axle wrap and the binding and unbinding of that, my take off jitters were effectively completely eliminated by a heavier duty leaf pack and Archive Garage Hammer Hangers.

You do have to cut off your factory hangers to put on aftermarket hangers but they are by far in my opinion well worth it, the factory ones are just piece of stamped thin steel I was able to bend mine with my bare hands, now think about 4,000+ pounds of truck having leverage on those...

 

So Im having issues with a vibration when I take off 0-10mph or so Think my angles might be a little off can anyone verify my angles for me I have a 12 Taco trd offroad JBA UCA King 2.5 ext front and rear deaver stage 2 and 3 deg shims skinny part forward
Zero at trans then
measured first shaft 4.0deg
then measured 2nd shaft 8.1deg
then zero on 2nd shaft and measured pinion angle 3.2deg

my calculations and dont think im doing this right but
angle 1: 4.0
angle 2: 4.1
angle 3: 3.2 or is it 4.9deg?
And not sure what my pinion angle is For some reason I think Im confusing myself on how to calculate these angles. any help would be greatly appreciated thanks.

 

I'll take a crack at this since I'm trying to figure out the same thing on my truck.

Your pinion angle is 3.2 deg. (Based off your info)

I think the thought process is to now use a carrier bearing spacer to try and make your 1st shaft angle closer to your 2nd shaft angle. (Or 2nd shaft angle closer to the 1st shaft angle)

When that is accomplished, then remeasure for pinion angle and use degree'd axle shims to bring your pinion angle close to 0 deg.

This is my interpretation of the correct process but please correct me if I am wrong.

 

My first and second angles are basically the same

think I need to somehow make them be less then 3deg but not sure how I can do that I cannot raise the carrier any higher. Guess I would need a a 4deg shim or higher but not sure how to go about it.

 

Having problems too. Trying to fix this or somewhat less annoying until I have enough pennies saved for a one piece.

My set up:
Bilstein 5100's for the max lift.
Stock leafs with add a leaf (Previous owners)

What I've done to fix so far:
OME CB drop. Doesn't really help
Replaced all U-joints and CB all OEM.
Now currently running the CB upside down with out OME spacer. Going to drive it for a few days and see the difference. Right now with the current configuration of the CB both my CB and Diff are less that .2° difference (pretty much same angle)

Below is my drawing of my angles. If anyone can help calculate coz I'm getting confused lol. Hopefully it's understandable.

Using the diagram that Key-Rei posted. Here are those angles

 

@mchabot1987, are you getting vibrations with these measurements? Just by eyeballing here, everything looks like it should run okay. Angles cancelling each other and whatnot.

*Edited to add*
A picture is worth a thousand words:

 

I saw that diagram and I think mine is very close that that. If I'm even measuring it correctly. I measured it like the image the Key-Rei posted. So I'm hoping it's good for now until I get a Tom woods.

Well I just flipped the CB today, test drove it a little and seemed better. I'll be driving it like that the rest of the week and see if I notice a difference. I'll post my findings.

I'm not sure if it's even my drive shaft now to be honest. I get odd vibration here and there when taking off. But while driving it's like a constant light vibe in the area of the CB.

I've slowly been correcting the previous owners awesome mods so just narrowing thing's down.

Edit to add: Also forgot I put a 2.5° shim at the rear. A while ago (was a friend of mine so was free 99. Just tried to see if that would help.