Drive Shaft Vibrations Solved Step-by-Step

slo2sixty, take-off vibe could be due to axle wrap and pinion angle being off, as BaconTaco suggests. When you get around to measuring, you might find that your pinion is level or slightly up (compared to the parallel angle of your trans/txfr) rather than the desired slightly down. Super rough guess, shoot back measurements for refinement. Also tell us us your Sport is x2 or x4, makes a difference on desired angles. See the pdf Two Options a post or five back.

 

Question for the subscribers out there, I have a DCLB 4x4 with dakars

I had the dakars w/o shims (1.5 up of the tc) and had a shudder/vibe at 5-15mph.

I figured axle wrap and shimmed the axle down to -0.5 of the tc. I still have my 5-15 shudder/vibe (maybe moved down in speed), but now I have this 20-35 vibe accel and decel that no amount of cb shims will fix (brought the shafts within 0.1, still no dice)

Any Ideas?

 

Osugoose, since no one else responded, I'll take a crack at it. With our dakars for the rear, did you do any lift or suspension mods to the front at the same time? I've been working on the theory that most of us who mix-and-match components and manufacturers end up messing ourselves beyond quick-fix. Personally, my low speed vibes were CB, and the high speed vibes were pinion. Goes on the theory that the super sloppy rubber CB allows tons of wobbles at low speeds, and as driveline rpms increase the center wobble (at the CB where the two shafts meet) flattens out and transfers their vibes to the trans/txfr and pinion respectively. It is true that axle wrap will also cause vibes (lots of you-tube vids on that), but they're usually pretty violent and only under heavy, repeat, HEAVY LOW END acceleration (gentle cruise from a stop up to speed with baby foot on the gas usually won't cause axle wrap issues). Also, axle wrap isn't a factor (well, less of a factor than other things) under deceleration, that's usually front end loading as weight shifts forward. Thus I ask what you did to the front end along with your dakars. Before you did the leaf shim, when you were 1.5 up at the pinion, did you try CB shims then to tweak your low end vibe? Or just jump to the leaf shim down conclusion, which seems pretty reasonable except it didn't work. I know, more questions than answers.....

 

Thanks so much for responding! The front is all OME(885). I read all the wrong
forums here before I started this project (or interpreted wrong, and here I thought I was being a good troll) Unfortunately I didn't measure the pinion angle before I started never thinking once that toyota wouldn't set it level or slightly below the tc. I had seen people need 2-3 degree shims on dakars here so I put 3 degrees on (through pin style) before the lift. I got the truck on the ground and sure enough 4.5 degrees high. So out came the pins and shims and I drove that way for a week (put in a spacer for further shims). This had low speed vibes around 10mph no matter how far I dropped the carrier bearing, no elimination, but lower throttle and it goes away. I didn't notice any vibes at higher speed that I could pin down, but my imagination sure had me going for a bit. BTW the OME CB had the best results in this configuration.

The next weekend I got my hands on some 2 degree shims (fat end facing forward) which put the pinion 0.5 deg on the money, and went for a test drive. That I learned what medium and high speed vibes feel like. 20-25mph was awful in accel and decel, and I picked up a 70mph vibe under accel. I shimmed the CB from 1.4deg all the way down to 0.1deg and the vibes never changed all that much. At this point it felt almost un-drivable so I took the shims back out and settled on the shim-less configuration for the meantime.

I tried the CB flip yesterday and could only get the first shaft up to 0.8deg down of the tc, this induced a sharper 10mph vibe. I then, in intervals, brought the first shaft down to 1.5deg (matching the pinion) and got more of a take-off vibe 5 mph (still sharp). I returned cb upright with OME spacers and called it a night.

After having a day to think about it here are my thoughts,

1. Having a long bed and non-tsb springs originally, is it possible that Toyota let my truck roll off the line with a u-joint at a zero angle?

Even at 43,000 miles, this would have toasted the u-joint. The only way to prove this before I drop $100 on new u-joints is to put the original springs back on and remeasure.

2. Is 0.5deg down too far for my pinion?

This will be tested with smaller 0.5deg stackable shims that are on their way.

3. If the 20mph vibes are cb related, why did they not go away with my cb adjustment with the axle shims in? And why can I not recreate them with the axle shims out?

Maybe not having aligned tc and pinion doesn't induce the cb shake because a more straight on pinion doesn't induce as much of a moment force on the 2nd shaft, which in turn causes lifting of the first shaft in the carrier bearing (the centrifugal force of which then would allow the second shaft to extend, forcing the first shaft even higher in the carrier bearing forcing violent shudder from the shafts.) Leads me to number 2.

4.I have to slow down. I love the new suspension, it makes the truck feel more like my previous car, a 2009 mini S. This makes me want to drive it like the mini, inducing more 10mph vibes. (Here's your laugh for the day, I'm 6'7" 280lbs, and my little brother is 6'9", now imagine us in that mini, we actually fit quite well, with the front seats touching the back ones, of course.)

Any extra advice you can give would be greatly appreciated!!

 

Yeah, I had to ask.... Excellent analysis Osugoose! Ok, here we go....

1. I'm not totally sold on the fact that the rear pinion CAN'T perfectly face the second half rear shaft. I crawled under quite a few prerunners and a few 4x's on my local dealer lot, all lifted, and the majority had their rear pinions, if not perfectly facing the rear shaft, at least UP in angle. My brain was in serious WTF mode. I also thought back to my very first post on this thread, where I solved my vibes the first time by aiming my rear pinion UP as well (turns out I was measuring from the incorrect place, but the effect was the same). Then that whole zero-angle-equals-ruin-your-u-joint concept crept in, and MONTHS later I was still f*cking with my incessant vibes. If you think about it, and according to my (not Toyota) mechanic, every time you start and stop your truck, the rear axle wraps to some degree, thus changing the "zero" angle on the rear pinion u-joint and allowing much needed lubrication of those ever so small needle bearings. So, zero angle is fine, and I'm stickin' to that story. Works great for prerunners anyway, and they have the same u-joints as us 4x folks.

2. No such thing as too far down, or up, as long as you can drive in peace without vibes. That said, I have been advised by earlier contributors to this thread that, technically speaking, 0.1 degrees is better. In other words, ZERO is perfect to eliminate vibration, and JUST OFF ZERO is perfect for u-joint lubrication. How far off zero? My truck loves 0.5, but I also have a double cardon in now so my angles probably really don't matter any more.

3. Huh. Now that's an interesting theory. I'll have to quote that here so other folks can follow our thoughts: "Maybe not having aligned tc and pinion doesn't induce the cb shake because a more straight on pinion doesn't induce as much of a moment force on the 2nd shaft, which in turn causes lifting of the first shaft in the carrier bearing (the centrifugal force of which then would allow the second shaft to extend, forcing the first shaft even higher in the carrier bearing forcing violent shudder from the shafts.)" Essentially, that's the exact theory of a perfect double cardon drive shaft system. The rear pinion and second shaft are pointing at each other (like a prerunner setup), the trans/txfr and first shaft are pointing at each other (ideal world, NOT the case with our toyotas), and the forces between the trans/txfr and rear axle are split at the double cardon joint in the center. With our trucks, our first shaft is down from the trans/txfr right from the factory, and we're left trying to distribute the subsequent forces on our own. I am tending to like your #2 conclusion more and more.

4. uh...... say what? slow down? Not in my vocabulary. On the other hand, if the vibes are only at 10mph, unless traffic really sucks in Tulsa, just don't drive at 10mph? Yeah I know, not a solution....

I would use those 0.5 shims to point your rear pinion directly at your second shaft and give it a drive. If it still vibrates, turn the engine off and get your "little" brother to push.

 

Thanks so much for the input! Right now I'm in a holding pattern waiting on the shims, but I'll post the process and results when they come in.

As of right now, the plan is to move the pinion down from +1.5, moving -0.5 at a time, within each of these pinion angles I'll shim the cb from about 1.0 to near 0 and record the results. If I hit my sweet spot, Hallelujah! I'll call it good.

If I still get nowhere, I prepared my backup plan today. Driveshafts Inc. here in Tulsa told me today that a balance would be 43.XX (I would do this after a complete u-joint replacement), or if I abandon all hope, a cv rear shaft (cut rear section, add double cardon) would cost under $400. Yes I am taking this with a grain of salt as it was site unseen and you have me expecting $1000+. If it comes to this, I'll do a full review and tell you all about the service and the finished product.

Thanks so much for the feedback and I'll keep you posted!

 

I will be reading this in full tomorrow when i'm at work LOL

 

subd

 

Just sayin.... Cuz I'm jealous.... PSU Taco85, you suck! And Osugoose, you double suck! If I had to do it all over again, I would have gone for the double cardon drive shaft straight off the bat, screw this months-worth-of-shims business. My double cardon was $1000+ because it was a complete custom duplicate from all new materials. PSU Taco85, the junkyard mod is a great idea. Osugoose, if they can just mod your existing rear shaft it will definitely be less expensive. I couldn't afford the downtime with my daily driver, so I had to pay $$$$ for the complete replacement. Had I been able to drop my old shaft off for a few days and do without the truck, I would have paid closer to $500 for the double cardon modification at a San Jose, Ca driveline shop.

Is it worth months of headaches messing with angles and shims, when a double cardon will solve the problem in a weekend? I dunno..... I had fun learning way more than I wanted to about drivelines, but.......

 

Hey Hey Hey now It's not done and in the truck yet, and I may not even go down that road.

And where's your team spirit? We're all here to share the wealth of our experiences right? And our shims that we ended up not needing.

edit: And tell me about knowing more than more now than I ever wanted to. Even as a mechanical engineer, I've never had to deal with anything more than a one piece shaft, and never more than 200rpm shaft speed, so this is like a 3000 level class assignment all over again. I need a deadline extension on this one though.

 

Tscot, i got your parts, thank you again. put the nyloc nuts on today, and came to the conclusion that i have misinterpreted you this entire time. i actually have 3.0 degree shims right now, i dont know why i kept saying 3.5. so basically with your set now i can go from 3 to 4.5 or 1.5 degrees. unfortunately still no changes in vibrations. i am however getting used to them now. do you think i should order some 2.5 and 2 degree shims? another question i have is that when i put the original 3 degrees on i had to get longer ubolts since i put the aal and the shims. the ubolts i got are just slightly wider than the stock ubolts, however i can still get them on. do you think this is causing any problems???

 

Hey dmeko0, give me your new numbers, after you've gone bombing around the neighborhood a bit to loosen the leaf springs. Takes a day or three for everything to loosen up and settle in to place after putting the nyloc nuts on, at least it did with me. And to summarize, you have the low speed mid-30mph vibes, and the high speed 55mph vibes, give or take, and nothing you did with the carrier bearing shim changed a thing, correct? I believe that's where we left you before I sent over some parts.

 

what are your part numbers for your double cardan? ( If you do not mind looking) My driveline shop says they cant modify my drive line.

 

I took my driveshaft out and took it to the drive shaft shop. They said they can not modify my 2 piece DS to add a CV. I have 2013 4x4 short bed. They cant find a replacement part for the spline to attach the CV. I dont have the lengo down yet . It is the part right after the carrier bearing. Anyone did the DS mod to a CV can provide the part numbers? Thanks

 

you nailed it tscot. 20-30 mph vibe, and 55 -65/70 mph vibe/hum (i think just a really fast vibration) i'll shoot you the numbers as soon as i get a chance to measure. crappy weather here in ky for the time being so hang tight. thanks again for the help.

 

Well the drive line shop said they want to put my DS on the balancing machine to see how it is acting. My DS is vibrating and binding what the heck i am so close to trading it in for a chevy and call it a day.

 

Fedz, to do the driveshaft properly on a lifted 4x, you "probably" (depending on lift height) need to have the front shaft lengthened just a tad, the rear shaft lengthened quite a bit, the slip spline switched from just after the carrier bearing to down just in front of the rear pinion, and a double cardan joint installed just after the carrier bearing. Try having that discussion with your driveline shop, and if you really want to get technical, don't ask for a CV joint make sure you ask for a double cardan joint (no, I don't want to start a terminology war on this forum, but there is a difference, and if the driveline shop is trying to find parts to attach the slip spline directly to a CV joint up near the carrier bearing they're building the wrong thing for a Tacoma, unless Fedz I misinterpreted your info).

 

TscotR214
My truck is bone stock and has very bad vibration on acceleration. I took the drive shaft to the shop and they say they can not attach a cv after the carrier bearing and can not build a new one. They spun my drive shaft and they say it spins perfect on the machine. Do you have any technical info i can take to these jokers?

 

Whoa. Bone stock. Hold on that one. We're in a different game here. Quick Google search... and I don't want to get into TSB's (Toyota Safety Bulletins) on this thread, but..... quoting from another source...

"This TSB (T-SB-0249-12) supersedes a previous the T-SB-0131-08 and now includes 2009-13 Toyota Tacoma pickups. The issue is that “some vehicles may exhibit a vibration felt in the seat, floorboard, and/or steering wheel around 15 – 25 mph caused by a second order driveline vibration.”

The repair procedure first calls for a test drive to confirm the issue. There are special tips for 4WD trucks:

Shift into 4WD High.
Lock the center differential.
Remove the rear driveshaft and test drive the vehicle.
The vibration will be completely eliminated if condition is a 2nd order driveshaft vibration.
If the truck does have a vibration issue then this TSB applies.

There are multiple parts that could be causing the issue. The applicable warranty for all these parts is:

EG8032 (R & R Engine Mount): This repair is covered under the Toyota Powertrain Warranty.
This warranty is in effect for 60 months or 60,000 miles, whichever occurs first, from the vehicle’s in-service date.
SU1222 (R & R Leaf Springs) and ST1202 (Install Steering Wheel Damper): This repair is covered under the Toyota Basic Warranty. This warranty is in effect for 36 months or 36,000miles, whichever occurs first, from the vehicle’s in-service date.
Warranty application is limited to occurrence of the specified condition described in this bulletin.
The Fix

Replace the Rear Engine Insulator (Rear Transmission Mount).
Test drive the vehicle again to see if issue is resolved. If not, follow the next step.
Replace the rear leaf springs.
Test drive again to see if vibration is gone. If it still exists, follow the next step.
Install the steering wheel damper by removing the steering wheel pad and screwing it into place.
Test drive and confirm the repair.
It seems that Toyota feels that one of the above fixes WILL fix the issue."

Fedz, do some google time and some dealer time. I don't feel you are on the correct track in this thread or at the driveline shop. I feel you should be getting informed via internet on the TSB and bugging the local toyota dealer, contact enclosed:

Rodland Toyota
7125 Evergreen Way
Everett, WA
(425) 353-8551

 

I have the TSB done to my truck, new rear tranny mount, new drive shaft and new leaf springs and still vibrating, Toyota has no more tricks, they gave me extended warranty in return. Do not know where to go from here.