Drive Shaft Vibrations Solved Step-by-Step

You need to shim the rear axle 2 degrees. Then check where that put the second shaft angle (the one that is 3.3 now). It should end up closer to 2.4, but not exactly 2.4. If it does match the first shaft exactly, then raise the CB just little bit to get about .5 degrees difference. Last, check your side to side driveshaft alignment using a string line between the first and third grease zerks. If the two shafts are not perfectly aligned, loosen the CB and bump it into alignment. This should get you smooth as silk.

 

Awesome! I'll do all that this weekend and post back. Thank you so much!

 

badger! are you saying;
-"If it does match the first shaft exactly, then raise the CB just little bit to get about .5 degrees difference."
cause, to get the proper working angle of the very front U joint he needs to calculate the first shaft angle minus the transfer case shaft angle ? which means that for him is 2.4 and it should be around .5?

 

What I'm saying is that shimming the rear axle should bring the pinion flange and the TC flange to about the same angle. That is a good thing. Shimming the rear axle will raise the nose on the diff and reduce the angle of the second shaft. That is a good thing too, but there is a chance that he could hit exactly 2.4 degrees and match first shaft exactly. That is NOT good. There should always be a slight difference, less than 1 degree between these two shafts. When the shafts are slightly different, the u-joint moves in a slightly elliptical path. This encourages the u-joint to move around the bearing cups and wear the joint evenly. If the shafts match exactly, the u-joint moves in a perfect circle about its axis. In this case the u-joint never moves and just wears in one spot. None of this effects vibration. A perfect match is fine for vibration. It simulates a straight axle. It 's just the u-joint that suffers.

Also that slight rise in the CB, if needed, doesn't effect the pinion or the TC angles. They remain in phase.

 

Wow, that was very in depth! I'll be tackling this today and that helps me to really understand the end goal!

 

LOL, obvious or not, people have a hell of a time wrapping their head around this. Part of the problem is trying to explain it in a way that actually makes sense.

 

They do

 

Thanks for the good information. Sub for this week end

 

Thanks everyone for the help! The axle shims worked great. Finally vibration free!

Edit: Just kidding. The vibes came back the next morning. I have since then been adjusting shim amounts at the CB. Still no good results. I now have a slight feeling that this all could be in my head and it's actually the snow and ice on the roads causing the vibrations. Unfortunately there's nowhere around without snow and ice where my truck will fit to test this theory. I forgot to test for driveline side to side alignment so I'll do that today. I know there's no specific numbers to aim for, so for now I'll just get my first drveshaft back to 2.4, my second around 2 or 3 but not 2.4 exactly. Then the diff input angle as close to 0 as possible. Does that sound good? I'll have to wait until breakup season to even test if this worked though.

 

That is great news!

 

Hello All,

This is one hell of a thread. I created a new thread yesterday before I stumbled across this one. I'm not sure the cause of my vibration is the angles. The thread goes more in depth but in short I'm getting a slight vibration and humming when I let off the gas pedal only. When I'm accelerating no vibration (stops immediately when I press the gas). I'm running a manual 5spd, just bought the truck used and I believe it's stock suspension. It's nothing extremely alarming but I didn't experience it with my last taco so I want to nip it before it turns into something worse. I get the vibration and humming even if it's in neutral. At first I thought it was just the resistance of the transmission but being I feel it in neutral that doesn't seem to be the case. Some other research turned up the cause is likely some wearing u joints. I wanted to get some affirmation before I start swapping parts.

Any helps is appreciated, link to my thread below

https://www.tacomaworld.com/threads...g-after-letting-off-gas.534824/#post-17183045

 

Bump for the edit

 

So I'm in the middle of doing this again. I took out all the shims from the cb and the lowest I can get it is 4.1 degrees. The vibration I'm having is almost a howling vibration only really noticeable below 20mph that sound like it's in unison with the tire rotation. I've already changed to the Ecgs bushing and it doesn't go away in 4hi.

My numbers are:
1st drive shaft




2nd drive shaft




Rear diff input




Edit: also this is how my driveline side to side alignment looks.

 

Sorry, did not understand before. Now I get it!, thanks !

 

Sub'd. My vibes are at about 1500 rpm. Only started in the last 10k miles (I have 71k) on the truck. Icon 3", Dakar rear springs. Looks like I need an angle finder.

 

Calling all driveline PROS


Hey Fellas. Got a driveline question. I have done all the work I think you will need to answer.

I have been having this weird driveline vibe from 38-44MPH and I have a feeling my rear axle shims are not steep enough. The vibes are happening at about 1200rpms the most when cruising, more-so on deceleration even when foot isn't on the gas or break. Also, I disconnected the battery to work on some electrical, when i got it hooked back up and drove there truck the vibe was gone for about 10 miles, then came back WTF?

Note: The trans angle was not zeroed, I measure it exactly as it sits


Truck Details:
• 2016 4Dr TRD OR
• 2" OME Lift Medium weight
• 3/8" carrier bearing spacer (OME)
• Full rear dakar pack (no leaf removal)
• ECGS BUSHING INSTALLED!
• Drives amazing except for 38-44mph
• Driveline has been professionally inspected and balanced
• Shims on correct way with skinny tapered end forward


Please let me know if I need steeper shims or what? I have gone all the way from 1/16" spacer to 1/2" spacer in the CB with no luck.

I used Spicer parts calculator to figure this out. I measured the angles with a phone app and used same side of phone to measure angles without phone buttons interfering.
http://spicerparts.com/calculators/driveline-operating-angle-calculator


Someone please give me some insight because I cannot figure this out for the life of me.

Thank you for any and all help!

 

That sounds almost exactly like my vibes, but you're a 3rd Gen.

 

Do you have a CB spacer in? I header you need to have the propeller shaft from the tranny to the CB straight and then mod the rear with shims. I am thinking my shims aren't steep enough, especially with my full dakar pack. Do you have shims?

 

I do have the CB spacer. I have the full Dakar pack too. I need to look at mine again to see if the spacers are in there. I took mine to a mechanic that does all my work. He changed out the CB, and had the driveshaft balanced. This whole driveshaft angle concept is new to me. Mine seems to be more rpm based than speed. Now that I know the feeling, I can make it happen in different gears. It seems crazy to have to go to a one-piece driveshaft.

 

Yah the 3rd gen is a whole new beast. The vibe is definitely specific to a small range at low RPMS