Drive Shaft Vibrations Solved Step-by-Step

I've been dealing with vibrations since I installed my lift and had given up on trying to fix it for for a while. I bought an angle finder and messed with driveline angles for weeks without any positive change. The last thing I did was install a 2.5 degree shim, which helped a little, but I am still getting vibs. The truck has basically been used only when necessary. I've had to start using it more recently and noticed that when my gas tank is full, I get less vibrations. As my gas gets lower and lower, I get more and more vibrations. I'm guessing that as the gas gets used there is less and less weight in the truck, changing some driveline angles? I can tell you I don't really understand how to properly measure driveline angles despite reading this thread over and over and over again. I am horrible at understanding of anything to do with math. Anyways, I am running the following setup:

OME 885
Bilstein 5100 @ lowest notch setting
Headstrong AAL
JBA UCAs
ECGS Clamshell
2.5 degree shim
Carrier bearing drop

Would getting a higher degree shim maybe improve the vibrations? Setting the 5100's to a higher notch (change the height of the front)? After noticing a drastic change in vibration based on the amount of gas in my tank makes me think someone here much smarter then me would know what to do.

 

I’m no expert but I can maybe help you understand or work through it a little. If I’m repeating what you’ve done I’m sorry, just saying in case. I don’t remember what I ended up with but I got both drive shafts averaging within like .02 difference or so. I did this by adding stainless steel washers to the carrier bearing, I ended up with 11 or 12 each side. I’d suggest that too. Some people had luck getting the transfer case and rear diff at the same angle. Mine are not. I had 3° sims in mine with the fat end facing aft. This didn’t help mine at all. I removed it and played with the shims till I was happy. it’s possible you need to instal the shims backwards depending what your angles are and see if that helps.

I’d recommend checking the angle at the transfer case and rear difs and see what they are. You might need to remove the shims or turn them around.

If the angles are good, then try to get the driveshaft angles as close to 0 as you can but make sure they’re not exactly 0. See if that helps.

Also check to see if the driveshaft is straight from case to case. The carrier bearing can move slightly left or right.

 

In regards to the carrier bearing, I went from stock all the way to OME carrier bearing drop plus 6 washers on each side. I found that just the OME carrier bearing drop helped the best. Installing the 2.5 degree shim helped the most, but still have vibes as my gas tank empties.

 

I see. I think it’s kinda odd. Maybe you’ll need more weight… or a one piece driveshaft… if I remember right @oakcity has a 2nd Gen and had vibes he was chasing. Pretty sure he got a one piece driveshaft and it fixed it for him. Sorry I can’t help more, good luck though.

I would think at the lowest notch you wouldn’t have many issues but that’s not the case.

 

This thread is misleading, and honestly it confused the matter for me more than explained it. I tried to better explain how to do it right (i.e., axle shims not carrier bearing drop) in this post:

https://www.tacomaworld.com/threads/opinion-on-drive-line-correction.733293/#post-26165101

Adding weight will change angles. Carrier bearing drops make it worse and will wear out u-joints prematurely.

 

Just consider me a smooth brain. I've read so much on the issue and still don't understand. I guess I was just hoping someone might know if I need a higher degree shim if the 2.5 degree shim helped reduce vibs, but vibes get worse as the gas tank, and therefore weight, gets lower.

 

Can you describe the vibes you have? When does it happen?

 

Almost no vibes while gas tank is full. As soon as my gas tank dips to around 1/3rd full, I start getting worse and worse vibs, in the 60-70mph range, as the tank get closer to empty..

 

I would start by measuring the angles with a full and empty tank and see where it sits.

 

Sub’d

 

So after my lift (3" front and 4" rear) with AllPro expedition HD leaf packs I mostly fixed my vibes with a 2 degree shim under the leaf packs and additional spacers on the CB. My diff. yoke is now .4ish degrees from being equal to my TC. I still have a very slight vibration at different speeds so is it worth getting a 2.5 degree shim to get as close to 0 between TC and diff. yoke?

 

Working on diagnosing drive line vibes and pretty stumped on how to proceed.

Here is my process and angles:
1) zero on TC and measure rear pinon flange: 10.2 degrees
2) measure 1st (front) shaft: 4.2 degrees
3) measure 2nd shaft: 5.4 degrees (1.2 degree CB working angle)
4) zero on 2nd shaft and measure rear pinon flange: 3.1 degrees

So, when I think about how to solve the angles, I could start with a 3 degree shim to resolve the 2nd shaft/rear diff working angle. But, I would still have a 7 degree offset between the TC output. and the rear diff input. I am seeing several methods, but don't know how to proceed. Anyone have thoughts?

 

Any recommendations on what I should do?

 

Your TC u-joint is at the maximum operating angle for stock 3.93 gears according to Spicer. Did you drop the carrier bearing? Either way you should try to raise the CB to get the TC u-joint to 3 deg or less (Spicer recommeded max. angle). Then once that is done, you need to correct your really high pinion u-joint operating angle (which will be even higher now with the CB raise) down below 5 degrees, and ideally below 3 deg, with axle shims and rotating the pinion upwards more in line with the 2nd shaft. I would make a guess at 4 deg shims being about right to get the CB and pinion u-joints to mirror and counteract each other. I would wait to buy shims though until you raise the CB and see how that affects the CB and pinion u-joint angles.

Note that the pinion will rotate up a bit under acceleration, and dip on braking, due to axle wrap. So keep that in mind too.

 

Thank you for the reply. I haven’t dropped or messed with the CB since the install of my shocks and new leaf packs so the TC angle has remained the same even at factory height which is weird. I’ve tried flipping the CB bracket but the other side of the CB bracket is thicker and does not fit in between the frame support so I’m out of luck trying to raise it unless I find a aftermarket option. What I do notice is under heavy throttle the vibration does go away so that gives me the impression when the axle wraps up the drive shaft is happy. I ordered some 3 and 4 degree shims. I’m going to try the 3 and see if that fixes the problem then go to 4 if need be.

 

The TC angle being stock is interesting. Mine is 3.4, and I have heard of someone else having their stock TC u-joint running somewhere between 1 and 2 degress. It would appear the transmission and/or carrier bearing mounts can allow a fair amount of play during manufacture.

Going with a 3 degree shim makes sense as a first step. I would recommend getting the Toytec one, or going with a steel one. You can go a bit wider with the shim than the leaf pack, up to 2.5 inches wide, if I remember correctly, and not have to worry about conflicts with the ubolts.

 

Being at 5.3 degrees at the TC is a little concerning but if it came from the factory like that I think I should be good if I keep greasing the zerk on time. I purchased the shims from headstrong-offroad which are made out of steel. I will let everyone know if the shims fix the issue once I get them on the truck.

 

Any luck with the shimming? I'm in a similar situation and it seems like there's no way to get my working angle less than 3 degrees. May need to shim my rear axle down 1 or 1.5 degrees.



But honestly it seems like I need to lift the front of my TC a degree or is...thoughts?

 

I put 3 degree shims on today which put my pinion at 3 degrees and the CB and 3 degrees. Most vibrations are gone but I do have a light vibration when coasting or light throttle which indicates when accelerating the axle wrap puts it in the sweet spot. I’m going to put the 4 degree shims on in a week or two and I believe that should solve all the vibration issues and give me 2 degrees at the pinion to compensate axle wrap.

 

I’m not sure what I did wrong but my angle measure off my rear diff is like 76°. I do have a ripcord camper on the truck it’s loaded down.

front driveshaft: 4.2°
Rear driveshaft: 0.8°
Rear diff: 76°

Trying to get measurements before I install my foam cell pro kit