Drive Shaft Vibrations Solved Step-by-Step

I have an All Pro Standard Leaf pack in the rear, I removed my block lift when I went to full mid travel setup, this weekend im getting my drum brakes fixed and gonna replace the U joints since they are cheap and see what happens after that, Ill need to find out what * shim I need for the rear

 

My bad, I missed the prerunner on the first read through.

If you are doing the u-joints, you might regrease the slip shaft while you have it out.

 

Back to the OP, I found the link below on a Google search and I can't believe it hasn't made it's way on TW, at least that I could find. Since I lifted my Taco I am now dealing with a vibe and contemplating removing it and going back to stock unless I can somehow figure this out. My main question is: what is the main goal? Is it to have a TC output and a rear diff output at 0 degrees with a matching angle in the middle, or is it to have joint operating angles less than 3 degrees? Currently my measurements are: TC=0 1st shaft = 4 2nd shaft = 6 Rear diff = 2 So 1st joint angle is 4 degrees 2nd joint angle is -2 degrees 3rd joint is 4 degrees If I shim my rear diff down to 0, I'm only going to be increasing the joint angle to 6. Subsequently in order to match my shaft angles (let's say at 5) I would still have a 5 degree angle at the rear diff (5-0=5) and my front joint would also increase to 5. Why wouldn't it be better to shim the rear diff up to reduce the operating angle of the joint? http://spicerparts.com/anglemaster/measuring-angles

 

Wow! I had no idea this thread was still alive. Geez. Main goal is to get in truck, turn key, and enjoy the drive without going frickin ballistic at the first hint of that darn stupid vibration. Rant rant. Ok, since the original posting way back when, this is my opinion:

1. Generally speaking, shim the rear diff up to just a degree or two below perfectly straight with the rear drive shaft section. The amount of axle wrap you get will depend on the weight of your foot on the skinny pedal, and, the stiffness of your leaf pack. In any case, or, in all cases, you want the rear pinion just a tad (a degree or two) below perfectly in line with the drive shaft. Medium lifts (2-4 inches) need a 3deg shim, larger lifts need a 4deg shim, I have yet to use anything over 4 degrees.

2. Drop the carrier bearing about 1/4 to 1/2 inch. It's better to keep it just a tad high, rather than low. For the two piece drive shafts, that puts the front and rear sections almost perfectly straight, within a degree, with the error on too high (drive shaft halves peaks in the middle at the carrier bearing).

3. There's nothing easily done to change the front angle coming off the trans / txfr case, so you're stuck with that angle.

4. If messing with it in the above directions don't work, pony up and buy a double cardan drive shaft. You will still have to make the adjustments above even with a single piece or two piece double cardan, but your vibes will be gone. Worth saying again. If the above adjustments don't do it, STILL make the above adjustments, AND get a new drive shaft. I'm still a fan of double cardan, mine has been great at all speeds.

 

The Toyota TSB seems to go against everything that has done in this thread. The TSB implies that the rear pinion is tilted down so it will be parallel with the section coming out of the transfer case. And people with the TSB done got their vibs completely eliminated.

Most people in this thread tilt the pinion up and are still fighting vibes.

 

This is what has me confused. Spicer info says run the diff output either parallel to the TC output, or parallel with the 1st shaft. Either has me regretting the decision to change out my shitty flattened stock leafs for some that actually ride good and can handle a load. This thing just has me dumping more money into the rat hole. I'm trying to decide to keep at it, or go with another leaf pack at standard height and remove my 884's and go back to stock.

 

Good observation Hans. I base my opinion on crawling under a bunch of trucks over the years at my local Toyota Stealership, and, without fail, every single factory or aftermarket lift on the lot has the rear pinion tilted up. And in speaking with the techs, they all tilt their personal trucks and customer trucks up as well. Go figure. Who knows, go with what works for you.

 

It's pretty hard to eyeball it. Even though the pinion is tilted down, it will still look tilted up because the pinion angle is still negative. It is not tilted down enough to create a positive pinion angle. The Toyota TSB shims only tilt the pinion down 2 or 3 degrees.

 

Nah, I'm old and dumb and blind, I don't trust my eyes. I used my digital angle finder, usually with the salesperson holding the notepad to record my numbers as I crawl around their lot. Also, at least from my experience, fat end forward on those shims is not at all the way to go. Everyone's mileage varies, so, it takes about 15min to swap the orientation of leaf shims. Try it down, try it up. You are probably absolutely correct in your observations. Thanks for the insight!

 

I measured the angle on the pinion flange and it's 2 degrees pointing up. I also measured my buddies stock TRD and his is exactly the same as mine. So what this tells me, is that a 2 degree shim (fat side forward) would rotate my pinion angle down to be parallel with the TC output........BUT this would increase the operating angle of the joint in the process.

 

avail for pm's, but unsub'd. this thread should have died months ago.....

 

Do I need to use collars or longer center pins for the leafs or can I just slide a shim in there and tighten back up?

 

Based on the Toyota TSB, with the fat end facing forward, yes that does increase the operating angle (joint angle) at the pinion. However that makes the pinion closer to the angle of the shaft coming out of the TC. That seems to be working for people who had the TSB done.

Since putting the fat end backwards doesn't seem to be working for most people in this thread, it's worth a try to the fat side forward per the TSB method.

 

TacomaJay09, have you tried shimming the pinion 0.5 to 1.0 degree up? Stiffening up the springs will reduce the axle wrap, meaning your pinion is no longer rotating up as far as it did stock during normal driving (ie not matching the first shaft angle anymore). Just a thought, what speed vibes are you getting, that might help us point you in a better direction.

 

I have a take off shudder and a vibe from 25-30mph. The 25-30 vibe is under accel or decel and throttle off conditions so pretty much any time I am between 25-30mph. I had no vibes before changing the leafs which were absolutely toasted.

 

I would try two 0.5 degree shims to bring the pinion up to 3 degrees, then shim down the carrier bearing, see if you can make some progress on the 25-30 vibe, the shudder should get better but may not go away, that might the CB bushing wearing out. My experience is that the toyota CB bushings are not as stiff as the cheaper replacements and give you more of a shudder.

Here is a pic of what a worn out CB bushing looks like for reference, you cannot see this with it mounted on the driveshaft so you have to measure the play.

 

I haven't shimmed the axle yet. I have been playing with the CB with no real improvement. What is considered excessive play in the CB? I can move mine around I'd guess a half inch or more without measuring I was also just reading about the new TSB and it appears that Toyota is installing new 4 leaf packs as part of the TSB with axle shims and shimming the pinion down with either 2 or 3 degree shims to 0 degrees and it is solving issues on stock trucks.

 

Again there are two lines of thinking here, and it seems to be because both could work and neither is a catch all for all cab/bed configurations and drive types. the TSB seems to work on some of the DCSBs and ACLBs, but I can tell you I had no luck on my DCLB. The way I was describing is what I used, it is the way toyota (subbed to spicer) originally designed and built them and it matches the spicer "diagram 9" For the phase of my driveshaft. Try one, if it doesn't work, try the other, see what works for you.

http://www2.dana.com/pdf/J3311-1-DSSP.pdf Here's the spicer pdf for reference.

Edit: Sorry, I never addressed your first question. Don't worry about the CB being worn out just yet, you should be able to get the mid speed vibe to go away even with a worn CB bushing. If you have a little shudder left we'll address that then. Right now lets tackle one problem at a time.

 

So last night I rotated the CB 180 degrees and the 25-30mph vibe disappeared. I still have the shudder. I also loaded my truck up with logs and rocks to help settle the springs which is for now making the shudder worse. When I flipped the CB though, my first shaft angle is at 2 degrees which is matching my pinion flange angle so I'm scratching my head why I have any issues at all. I'm thinking that the the CB is definitely worn because I could see some torn rubber through the holes in the bracket but also that even though the angles match at 2 degrees, that the second shaft angle is too steep for the CB and the CB is the weak point. I have no idea where to go from here and it's driving me nuts.

 

You are on the right track, now that your 1st shaft and pinion are at close to the same angle, and 25-30 mph vibe is gone, we can work on your shudder, the best way to do this is reduce the stress on the CB. No matter what, we want to keep the 1st shaft and pinion in proportion with each other. (For example, to get the CB back to its original position, you need to shim the pinion up 2 degrees or so.) From here, you want to reduce the 1st shaft to 2nd shaft angle and 2nd shaft to pinion angles as much as possible while keeping them proportional. This should help the shudder, but if the carrier bearing is too worn, you may still need to replace it.