driveshaft vibration

crajack135 · Jun 30, 2021

Hey guys, I've been lurking for a while now. I just bought my 2018 tacoma offroad back in December and it came with king offroad racing front and rear suspension and icon aal pack. Last weekend I upgraded just the leafsprings to deaver stage 3 leaf springs and now have a noticeable vibration accelerating to 25ish mph, and when decelerating it starts at about 15 mph and gets very noticeable at 5-10 mph. The vibrations are also the same in 2wd and 4wd so I don't think a clamshell bushing would fix it.

So I didn't realize it was a thing before to check driveshaft angles because there were zero vibrations before. (I also realized while doing all this that it already had about a 1/4" shim on the carrier bearing)

So i bought a digital angle finder and zeroed it out on the Transfer case flange.

Then I put it on the first shaft and it read 5°

Which means my first pinion angle is also 5°

Then I put it on the rear shaft and it measured 7.2°

Which means my middle pinion angle is 2.2°

Lastly I zeroed it out on the rear diff flange and put it back on the second driveshaft and it read 8.2°

So that tells me my rear pinion is 8.2°

So I know I need to put a degreed shim under the leaf springs but I'm just not sure what it's supposed to match. I remember reading on here I think that the rear pinion angle is supposed to match the angle of the first drifeshaft which would mean I need a 3° shim to make it 5.2°. But I also thought I remembered reading that the pinion angles need to be less than 3° Which would mean that I need a 6° shim and to possible adjust the shim under the carrier bearing. So I'm just a little confused as to what's correct. Thanks for everything guys

hyrule_trd · Jun 30, 2021

I’m not an expert by any means but I’ll tell you my thoughts.
I’m not so sure the first flange will be 5°. On mine I would zero it out using a metal bar off the flange and then check the angles of the driveshaft. The flange was never the same as the driveshaft. Looking at my last post in the thread below, my driveshafts were 4.54° from zero-ing out at the flange. I had put a 3° shim in the back but ended up removing it. Your best bet might be trying to make the 2 shafts average the same ° angle down by adding washers to the cb. You may need longer bolts as well. I ended up following someone’s advice and bough meta fender washers that worked great. I have about 10 washers on each side. Another tip, check and make sure the shaft is lined up right. It can be moved slightly left or right at the cb.

Also check this thread if you’ve not seen it, the also talk about where your vibes might be based on when you fee them. Good luck! https://www.tacomaworld.com/threads...ved-step-by-step.244535/page-51#post-25843778

crajack135 · Jul 1, 2021

Thanks for the reply. Yeah, that's what I did, took a metal bar and zeroed it out on the flange and got the angles of both drive shafts off of that. That's how I got 5° for the first shaft and 7.2 for the second shaft. I didn't think you wanted to make the 2 shafts the same °, that way the 2 shaft bearings at the joints or something wear evenly. Atleast that's what I thought I read on here somewhere. If I add washers to make the cb lower, and then it would be more than 5° Which I thought wasn't kosher. I did notice the slop left and right on the cb, so i took my laser level and made sure it was straight with that.

crajack135 · Jul 1, 2021

Crom said: ↑

How I measured my drive line angles.

The way I did it was put my digital angle finder on the transfer case flange and set the unit to "Zero". That's my reference point.

Then hang the angle finder on the first shaft. The angle of the first shaft in my truck is 5.05* down. This is also the angle of the first u-joint.

Then hang the angle finder on the second shaft. In my case it was 5.75* down, Subtracting the two slopes I get 0.7* for the second u-joint.

Then using the a flat bar I measured the flange of the pinion and got 2.95*. The angle of the third u-joint is 2.8*.

Now comparing the slope of the first shaft 5.05*, minus the pinion angle 2.95*, it looks like my pinyon is -2.1* down relative to the first shaft.

Pinion angle should really match slope of first shaft.

EDIT: 11/1/2016 - Measured again after modifying spring pack:

First u-joint operating angle (OA), closest to xfer case: 4.85° Down,

Second u-joint: 2.35° Down,

Third u-joint angle is somewhere between 2.45° - 3.9° Down

Which means Pinion angle is within 0.10° - 1.55° Down, of first shaft.
I can't get more accurate on the pinion without putting rear axle on jack stands.

Here is some tech that I'm using to help me:

From the factory the Tacoma has a two piece drive shaft. According to Dana who manufactured the center support bearing and shafts, I would want the pinion angle to match the output shaft of the transfer case.

I snipped this picture out of their documentation.

But there is more to the story, in practice, a lot of *performance* shops will make the pinion 1*-2* negative. The reason for this is because, when accelerating, the pinion will rotate up because of torque. In theory, when it's under load it will match or be very close to the slope of the first shaft.

This is a good article with references to recognized industry experts and explains what they do in setting up built vehicles.
Click to expand...

Here is where I saw it, that's where I got the idea that the first shaft angle had to be the same as the last pinion angle.

hyrule_trd · Jul 1, 2021

I gotcha. Mine aren’t perfectly the same just really close. I originally tried the way you did with no luck and even had 3° shims. I just tried them out before really measuring.
Here is where got my advice from in that thread. The method you tried is one of them.

TscotR214 said: ↑

Update: A different method, probably easier and better

Let me start off by saying badger is a frickin’ Rock God from Mars when it comes to this driveline crap. I mean really badger, why let all of us newbies fumble around, you’ve got every answer and every angle covered! A BIG NOD AND THANKS TO BADGER for infinite wisdom. I was digging around another post when I came across some extremely useful information, that I feel was getting buried amongst page after page of responses. I want to quote badger here, so it’s a little more accessible. I didn’t ask badger first, so hopefully this isn’t creating bad forum blood, but again all credit goes to him for the following:

Quoting badger:
“Here are the three possibilities [for fixing this driveshaft shudder sh*t]:
1. (my [badger’s] preferred method and Toyota's method) Align the TC output shaft and pinion shaft to be parallel. On most trucks with well designed lifts they will already be correct. Then drop the CB a small amount until the two driveshafts almost form a straight line (less that 1 degree). This geometry puts the 1st and 3rd joints canceling. Joint 2 is (near) zero. Side effects > none.

2. (Beefy CB drop) Align the TC output shaft and pinion shaft to be parallel. On most trucks with well designed lifts they will already be correct. Then drop the CB until the rear shaft forms a (near) zero operating angle with the pinion shaft. This geometry puts the 1st and 2nd joints canceling. Joint 3 is (near) zero. Side effects: greater operating angle at the TC joint will cause faster wear and may limit high speed operation. DL clearance is reduced.

3. (Spicer diagram) Raise the CB until the first shaft forms a near zero operating angle with the TC output. Adjust the pinion angle to be parallel with the first shaft. This geometry puts joints 2 and 3 canceling. Joint 1 is (near) zero. Side effect: Driveline clearance will be increased. A custom crossmember will be required to relocate the CB. Operating angles at Joints 2 and 3 will be increased causing accelerated wear and possible high speed limitations. This method is commonly used in trucks with long shafts and little lift where the angles are not a concern. Most commercial trucks are set up this way.

Note 1: Joints should never run at a dead zero operating angle. That's why I keep saying "near zero". A joint that operates at zero will not rotate on it's needle bearings and will wear in one spot on each post/cap. The bearing must operate at a slight angle to move lubricant and to wear evenly around the post/cap. Joints can, and should run at a zero relative angle when parallel axis are established.

Note 2: Toyota did not make any mistakes in the design of this drive shaft system. They chose option one for the same reason I chose it. They used a 2 piece shaft to eliminate critical speed instability, and they designed it for the least side effects. My only complaint, or perhaps question, is why they used such a wimpy carrier bearing. I don't know. I think some of the issues stem from that, and I plan to change that on my truck eventually. For mild lifts of 3" or less the geometry can pretty easliy be returned to optimum by understanding the reasoning behind the geometry.

I think that's about all there is to say on the subject.”

End badger’s awesome wisdom quoted.

Turns out my originally posted solution was something along the lines of badger’s Solution #3, in that I had aligned the rear diff pinion darn near (0.1degrees) perfectly in line with the second shaft, then “tuned” the carrier bearing drop. Worked, but I was a little concerned over long term wear, as badger pointed out.

So, I decided to try badger’s Solution #1, along the lines of the OEM Toyota alignment. Step by Step:

1. First, I measured the transfer case pinion angle, and zeroed my digital gauge against that measurement. After getting multiple different readings from trying to use a socket on the u-joint caps (mine have a lock ring over the cap that makes the socket rock), trying to find a flat place on some part of the u-joint yoke that equaled the true pinion angle (couldn’t find any that weren’t a degree or two off) etc, I finally just placed a flat steel bar against the pinion, uh, what’s that part called… plate? See photos #1 and #2.

2. Next, with the gauge at zero (if your gauge doesn’t reset to zero, don’t sweat it, just remember the angle it measured), I slid back to the rear pinion and measured from the same place, that flat, uh, plate, and read that angle. Before I messed with any mechanical changes, I noticed that my readings were damn near exactly 4degreees off of each other (with the transfer case pinion set at zero, the rear diff pinion read 3.9degrees on the gauge). Remember from my first original post I had installed 4degree leaf shims. AHA. I f*cked up! By exactly 4degrees, as it turns out. Upon further reading the other awesome but lengthy post, it was either badger or maxamillion2345 that had mentioned the All-Pro expedition leaf pack didn’t need a shim. Double f*ck. Called All-Pro, sho’ ‘nuff, no shim required, their leaf pack doesn’t significantly change the rear diff angle in any way. Triple f*ck for stupidity on my part. At this point I’m holding Stupid Gun to my Loser forehead….. Whatever. Live and learn, hopefully. Promptly threw the truck on the lift, yanked those shims, and now both pinions read pretty much the same. See photos #3 and #4.

3. Thirdly, now time to mess with my favorite carrier bearing. Promptly when out and purchased an air tool for my socket set, my wrist was getting tired. (I have a hot girlfriend, wrist isn’t used to that much repetitive motion). Anyway, put the digital angle gauge on the rear shaft, set it to zero, and measured the front shaft to see the difference. Following Badger The Great’s advice (is my nose brown enough yet?), I dropped the carrier bearing about, oh, 10mm I think, using the ToyTec spacer I had and that original hardware store washer. Drove it, stuck another washer in, drove it, removed the spacer, drove it, messed with it, etc, until it’s fairly smooth. A bit of vibration at high speed, over 60mph, but right now both driveshafts are to within 0.1 degree of each other, so I have a bit more messing around to get them more like a full degree apart rather than a tenth of a degree, to lube the needle bearings. See photos #5, #6, and #7.

So here’s my point: while my original post worked, on a couple of different vehicles, it appears I was choosing to align the wrong parts, from a longevity standpoint. As badger pointed out, Toyota is not stupid, and it was out of frustration and ignorance that I had bagged on them so heavily. This second method took a total of 45minutes, including some road test time, incredibly easy, productive, and fast. Wish I had done it back in March when I originally lifted my truck……

In reading other posts, there seems to be tons of confusion over the terminology (TC output shaft, TC pinion, TC shaft, first driveshaft out of TC, etc etc), and certainly where and how to measure. I read lots of frustration and confusion amongst the posts. Hopefully this second method, and the enclosed photos, will help.

Click to expand...

crajack135 · Jul 1, 2021

So not sure how I missed this, but my csb is about 1/8" off from center with my laser level pushed over as far as it can go. I also added 10 washers to each side of my csb. I zeroed my angle finder on the flange with some flat stock and the first shaft is 8.4°, the Second shaft is 8.6°, and the rear flange is 1.4°. I feel like those angles at the flanges are way too much. Maybe I'll just get a 3° shim and see what it does.

hyrule_trd · Jul 1, 2021

Good luck. The shims at @HeadStrong Off-Road have slots making them much easier to put in. If you have oem style U bolts, the shims will not be able to move out. They are too wide to slide between the bolt openings, if you’re worried about that.
Or jet a one piece drive shaft, that’s supposed to fix it too. Those things are too pricey for me atm and most my vibrations are gone.
Someone suggested the trucks are just like that and have vibes that come and go.
Maybe a dumb question but did the new leafs go in the right way?

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