Drive Shaft Vibrations Solved Step-by-Step

I think when they measure, they zero it to the flange and then measure the difference from that with the other flange without resetting the zero.

while the actual shaft angle in relation to the flanges will change, the difference in angle may not change much.

 

Indeed. Forsooth. or whatever word you chose. I think I get it.

I will measure this weekend and report back. Should be interesting, because the eyeball test, sure does say it it shouldn't work.

Also, just got back from my first cargo load in the back with the new suspension. Truck did great, although it was only a 20 pack of bud light.

I can't wait to get the rest of my rigging ans see how it handles the high banks of Padre Island National Seashore-4 weeks to go.

 

P9HST2, I would venture to say that your success stems from the fact that you stuck with Icon components throughout. I've found that if you stick with the same manufacturer, rather than mixing and matching from different suppliers, that both install and vibe issues go quite smoothly. Congrats and fingers crossed to you! I know there are quite a few folks who are probably grumbling the fact that a lift cured your vibes, rather than causing them.

JiggyZ, similar thing, sounds like you went with a full kit also. For your measurements, it sounds like you are using a gauge that doesn't have a "zero calibration" button. When we speak of "zeroing out" we mean "put the gauge where you want it, ignore the reading on the dial, and hit the "zero" button", so that your measurement now reads "zero". Then, all subsequent measurements will be single digits off the TC/Trans. If you're getting absolute 85's etc, you just have to do a bit more math. Write down your first TC/Trans measurement (call it 83deg), then measure your first shaft WITHOUT changing the orientation of your gauge. That means you need to measure the flange with the SIDE of your gauge (up against a small steel file works great), then measure the shaft with the TOP of your gauge, without rotating the gauge, and pressing the top of the gauge against the bottom surface of your shaft. Also, keep your feet sticking out the same side of the truck while you measure to maintain the same orientation the entire time. Write down that number (call it 88deg) and subtract the two numbers (83deg minus 88deg equals -5deg, which indicates shaft is down (negative number) from flange, as it should be.

And luka, you are correct, everything is measured from zero at the first TC/Trans output flange. If you stick with a full kit from the same manufacturer, they usually produce their AAL's or full leaf packs with the correct angles to begin with so you don't need leaf shims. In theory.....

 

tscot, flipped the shims to skinny end forward to get that pinion pointing higher towards the rear shaft today. also installed the bushing in the front differential. needless to say, the bushing did wonders as i expected it to. that was in a different thread on here. ( http://www.tacomaworld.com/forum/2n...differential-bearing-vibration-thread-19.html )but anyone with the growling issue that goes away in 4wd def needs to look into the ECGS bushing install. as far as vibrations go i am very happy with the progress made today. no more vibration on the slow down, very small amount of vibration during acceleration at around 23 mph. and just a little vibration still at around 50-60. compared to where i was this morning and where i am now, i am thrilled. hahaha. it was really bad before i worked on it today. i didnt measure the angles because i forgot my angle finder at the house when i went to the shop today. i know that the rear pinion is not pointed directly at the rear shaft as of now, but i should be able to measure those to and get a pretty good idea of how much more shim i'll need correct? my other question is say i need another 1.5 degrees of shim. i've got the toytec 3.0 degree shims then i've got the sets of 1.5 degree shims you sent. it would be okay to use those together correct? considering the toytec shims bolt to the leaf pack and your shims are sliders. i suppose i could bolt them in with the leaf pack as well or no? thanks for all your help man. i hope i can put in some input to help others as well.

 

dmeko0, sounds like good progress! Congrats! You still have an angle off by just a touch, notice your vibes are at speeds about double each other? Around 25mph, around 50mph, that means you're hitting that resonant wave at two spots consistently, so I suspect just a touch of CB shim will fix that, but of course the numbers will tell us more. If the numbers do point to more leaf shim, you most certainly can stack those shims, they're made for doing just that. Bolt them in, slide them in, use chewing gum, whatever. By the time you crank down on your leaf u-bolts they're not going anywhere. I just installed a rear diff skid plate over the weekend and found myself torquing the crap out of a pair of u-bolts that hold the skid plate to my rear axle, then had to laugh at myself. There's no need to tighten skid plate bolts beyond hand snug, but I was completely in the leaf spring shim mode of thought, so out came the air wrench, the breaker bar, the torque wrench, and an extra Red Bull to beef up my skinny white boy arm strength. Drive your truck the way it is for a week or two, let things settle in, maybe let some snow melt off the driveway, and let us know how it's driving. Congrats again!

 

What I am confused about is on the angle measurement is once you zero out on the front flange, then the measurements on you drive shaft would be 80+ degrees difference, no matter what. In order for them to only be a few degrees off the drive shaft would need to be pointing more or less in the same direction at the TC flange. I just don't see any way around that. I have the Harbor Freight angle finder BTW.

 

Jiggyz, do you have the digital angle finder from Harbor Freight or the analog version ?

Unfortunately I'm on my way to Joshua Tree and will be out of internet range soon, but hopefully some other members will chime in and give you a hand.

 

tscot, measured the rear pinion vs rear shaft. didnt do it zeroed vs 90 degrees but rather zeroed on the rear shaft and kept the gauge the same way so i came out to .9 degrees. another degree of leaf shim ya think? order some 4 degree shims? if i stacked i'd be at 4.5 degrees which i would imagine is a bit too much. the pinion is pointing a little farther down than the rear axle. i'm so close i'm almost afraid to change it! haha but if i get all the vibe out i'll be ecstatic

 

Nice write up, as far as determining why some Tacomas vibe issues are fixed in one manner & unresponsive in another is a window of futility, I've done rear lifts on at least 50 Tacomas now (mostly 2nd gens.) & although I'm prepared with spacers to drop carrier bearing & make the changes I have not had 1 Tacoma yet develope a vibration after lift except for mine...It seems that the ones that do have a 1.75"-2" lift

 

Ok so i finally got my measurements as per the first post. Hope i did it right. I used my phone with the rigid level app. For those who didnt see my post i only have a 0-10mph vibe.

First shaft is at 6.0
second is 10. (reset here)
and got 2.7 for my rear diff

so from reading the first post im guessing that i should add some washers to the carrier bearing to drop the second number down while raising the front up untill they are pretty close and my vibes are gone??

 

No problem. I think what you want us to do after zeroing out is to place a side of the angle finder rather than the magnetic bottom on the drive shaft, that would give a comparable reading. I was going magnetic to magnetic. Correct me if I am wrong.

I have the digital angle finder, just like the one you used to have.

I have also noticed a bit of take off shudder, and I think I am feeling something around 60, hard to tell with the 886 coils and no bumper.

At any rate I am going to slap the new bumper on in a couple of weeks and readjust.

I will get reading to the forum, once I have this angle thing figured out. Thanks again.

 

Haha, no offense but are you guys trying to split an atom or cure a vibe ?

& to the guy that installed shim skinny end forward, your sending the pinion down not up (assuming by "forward" you mean towards front of truck)

I mean all that info on +/- degrees is good to know in any event...carry on..

 

4wd, on second gen tacoma the shim positioned skinny end forward (towards the front of the truck) raises the pinion angle. i thought the same thing myself until i actually had the thing apart and was able to take a look and think about it. but yes, after grasping this driveshaft stuff, i'm pretty sure splitting an atom would be a cake job.

 

tscot measured rear shaft vs pinion again today. zeroed on shaft, pinion angle is at 89.1 still. i know that getting them perfectly strait would be putting more stress on the u-joints, dont necessarily want to do that unless itll fix the vibes. so my question now is, should i go with a 3.5 degree shim or a 4? 4 should put it basically right at 90.1 degrees relative to the shaft, 3.5 would put it at 89.6, leaving the pinion just a bit lower than perfectly strait, theoretically that is. i know it wont come out perfect just because i'm adding the degree in theory and i will obviously probably still have to fiddle with the carrier bearing. is there any different protocol on that besides getting them as close as possible without being perfect? which do you think? i'm trying to get these babies ordered so i can, lord willing, cure these vibes this weekend. thanks man

 

From the OP :

You want to read 90deg, indicating that the long line of the drive shaft is perpendicular 90deg to the short line angle of the pinion flange and thus your rear pinion is perfectly pointing physically slightly up and now directly at your rear half shaft. After a lift, this will require you to use leaf spring shims between your axle and leaf springs, usually with the FAT END OF THE SHIM WEDGE FORWARD

Isn't that shim orientation backwards ?

 

I believe so....skinny end should face forward.

 

Hey all, thank you for catching that skinny end thing! Brain numb. Darn atoms, always spinning around the wrong direction. Or was that electrons that spin? No, wait, it's the nucleus, no, that's wrong, maybe better to just stick with molly-cools. In any case, it really does seem like nuke physics would be simpler than vibe eradication sometimes.

dmekeo0, weren't you a contractor type? Got a belt sander? Totally fair game to take those aluminum 1.5 shims and just sand the ridges off, then go a touch more to make a 1.0 shim, which you could then slide under your 3.0's to try the 4.0 approach and see what happens. No cost, maybe a bandaid or three. And if it does work, really no harm in leaving them in. The u-bolt compression really doesn't allow things to move around, which is a good thing.

 

Jiggyz, you are correct in using both the magnetic side and then the non-magnetic side on a digital angle gauge when zeroing. I'll have to snap some photos to post, just to clear that up. Thank you for the clarification.

 

Does anyone know what size the carrier bearing bolts are? I went to add more of a spacer to them but the stock bolts aren't long enough. It's my only means of transportation or I'd pull them out and take them to the store. Thanks in advance!


Edit: searched and found it m10x1.25 if anyone else needs it.

 

i was going to say, i found myself driving to lowes, pulling into a spot, getting my 17mm socket if im not mistaken, taking out one carrier bearing bolt, running into lowes, matching it up and getting 2 a bit longer, then going back out and replacing it just because it was my daily driver as well. glad you found an easier way to do it.