vibration from 25 to 45 MPH

With the rear axle shims, do you need to take the nut off your center bolt on the leaf pack to install the shim or do you just slide the shim in between the axle and leaf pack? I cut off the excess threads on my centering bolt when I installed my AAL. If it bolts in the leaf pack than I need new centering bolts. Thanks!

 

Nope, the leaf bolt remains tight, don't touch it. Yes, the shim slides in between. The thread side of the leaf bolt doesn't matter. The round head on the underside of the bolt is long enough on mine to pass through an extra 1/4 inch shim and enough to engage the location hole in the perch.

You lift the truck and put the rear of the frame on jack stands. Then remove the wheels, disconnect the ebrake bracket on both sides, and remove the top shock nuts on both sides to allow extra droop. Make sure you bend the brake line brackets enough to allow a little more droop than normal. I put 2 more jack stands under the axle for safety, and use the floor jack to raise and lower the axle from under the differential. I then jack up the axle slightly and fully remove the u-bolts on both sides. Then I drop the axle one side at a time letting one side catch on a jack stand and the other side free to keep drooping as I lower the floor jack. The round head of the leaf bolt pops out of the perch and is exposed as the axle drops about 1 inch lower than normal full droop. You lay the shim on the perch and the head of the bolt passes through the hole in the shim and back in to the perch to locate the axle as you raise that side back up. Then I do the other side. Then I bolt everything up and torque it all up. I always check the ubolt torque once a day for the next week for safety and then a followup after another week, you can never be too safe.

 

Thanks for all the info SnoBoarder. I think I may get an angle checker at Harbor Freight very soon. I will get back to you with the angles.

 

Hey tacoma snow I have the exact same kit and the exact same problem if you find anything out I would really appreciate the info and I will do the same. Does anybody have the dimensions on these tappered spacers. I have access to a machine shop and would like to whip some up this weekend if possible.

 

If you are referring to the axle shims, these are the dimensions I built. Substitute your angle, because each of the 3 driveshaft types discussed require shims that alter the pinion angle 3 different ways, so a shim that works for 1 person may not work for you if you have a different driveline setup.

Length: 6 inch
Width: 2 3/8 inch
Bolt Hole: 5/8 inch on center
Angle: X Degrees

You can get any custom shim you want here. He made mine and mailed them the next day.
http://www.4crawler.com/4x4/ForSale/Shims.shtml

Just remember that trial and error is not the way to approach these adjustments.

 

Right on thanks snowboarder sounds like you know a lot anout these problems. I appreciate the help

 

I hate driveline vibrations. I have spent hours and hours wrenching and measuring and testing but I have learned a lot and still have much to learn. I eliminated every vibe except 1, and I have no Diff Drop either.

Update: I installed my custom shims for my 1 piece single cardan design today. The goal for that driveshaft ONLY, was to match the angle of my front u-joint to the rear u-joint and I did that nearly perfectly, with some negative angle to compensate for some upward axle wrap, and I still have a harmonic vibration passing through 50mph. So I'm shipping out my driveshaft to be upgraded to a double cardan design.

I get to go back to the OEM Toyota 2 piece drive shaft so I'll take angular measurements and see if I can cancel out the 3 u-joint angles with the parts I have on hand, and post up my angles and what I try. I will say my truck is smooth as glass (amazes me) except for that 50mph harmonic, so I'll know right away if I make any progress with the 2 piece. I'll have it for 2 weeks until mine comes back from the shop.

 

As promised, I did some tests and measured some angles on my OEM Toyota 2 piece this week as I shipped my 1 piece out to be upgaded to double cardan. As soon as I installed it, I noticed the background vibrations and some take off shudder. Here's a pic of the my angles with and without the Carrier Bearing Spacer kit.



My knowledge of 2 piece driveshaft tech says that the center U-joint angle is supposed to cancel the front flange angle, or in other words, the front section should simply be an extension of the front flange, leaving only the 2 rear most U-joint angles to worry about angle cancelation. If I'm wrong, somebody please chime in, but that's not the case in this example.

I don't have that smooth as glass driveline right now, but it isn't terrible either so I'll leave the cb spacer in and drive it. Just consider that + or - 0.5 degrees can make all the difference on U-joint operating angles and the vibrations that it can create, so your angles and results will probably be slightly different. Also worth mentioning is that my rear flange measures 4.5 degrees under static conditions only. It wraps upwards at least 1 or 2 degrees under load. That means any axle shim I'd fab up would be about that much more or less than what I'd calculate, depending on which of my 3 driveshaft styles I'd be setting up.

 

I have a 08 tacoma dbl cab with 2.5" billy shocks with AAL 1.5"/ billys. I noticed some vibrations during acceleration. Has anyone noticed with their lift that's similar? Nothing else, everything is stock except for the suspension.

 

Awesome animations SnoBoarder. Very helpful. How do you recommend aligning the 2-piece drive shaft horizontally? Referring to picture in post #28.

 

I used string from flange to flange but eye balled it most recently.

I said earlier that it wasn't that bad with the carrier bearing spacer but in reality, I hate it. I could never live with it and would probably shim the rear axle to try to improve it. The take off shudder is really noticeable too now, so I miss what I had. I have another week to go until I get my single cardan 1 piece back from the shop. I opted not to pay an extra $200 to upgrade it to double cardan because the shop did confirm my suspicion that the u-joints were assembled out of phase. I knew there was another factor, my angles were really close and I should have been vibe free at all speeds.

 

Awesome write up! Though you have opened up a whole new can of worms for me that I would have never thought of, I've learned a lot just from reading this thread...thanks.

 

hey i just installed a fabtech 6 inch in my 07 taco. A day or so after i had it installed i noticed a vibration in the gas pedal... but only when theres power being applied to the drive line. is this a drive shaft issue or something completly different????, ive heard of guys putting in a tom woods one peice but i dont know if this complies with this issue.

 

sound like u need carrier bearing drop or/and shims for rear under spring.

 

I have a brand new 09 DC 4x4 taco SR5. I am going to try and get my dealership to to the suspension TSB on my truck since my VIN falls in line with the TSB and the #'s on the leafs also. I am thinking about buying 5100's for all 4 corners and just giving them to the dealership to install during the TSB instead of the TRD shocks. I dont want a huge lift, but I want to set the fronts to 2.5". Will I end up experiencing any vibrations after all this is done?

I am confused because I was reading all these threads saying that the vibrations were caused by a bearing in the front differential. They thought this because if you switch to 4wd the vibrations would go away, but come right back when you go to 2wd.

 

Nice diagram, man!!

 

Ok, I'll chime in, maybe it will help, maybe it won't...

A Double Cardan style driveshaft, and possibly a rear axle shim, is one of the best known cures. Do not get the cheaper Single Cardan style. I have found it impossible to fully resolve all vibrations with that product.

Axle wrap can play a role in what you are describing. For example, let's assume you feel a vibration at 45mph. Try going up a long hill while heavy on the gas at 45mph. There is more load and therefore the pinion wraps upward slightly more causing more or less u-joint angle difference. Note the vibrations. Repeat going down the hill while very light on the gas, at 45mph. Compare the vibration felt downhill with the vibration felt uphill. This test will tell you if you need to shim the pinion up or down. Maybe this doesn't even apply, but it's good to know anyway and hasn't been presented in this thread yet.

Another option is to measure your angles and get a set of axle shims (and possibly the CB spacer as pataco suggests) and work with your existing Toyota driveshaft. You'll want to shim the pinion upwards (fat side of shim towards the rear). I'm actually going to swap driveshafts again, and re-shim again. I've not been satisfied with my Tom Woods Single Cardan and tired of dropping cash on shim sizes. I'm going to work with my Toyota driveshaft to see what I can do.

AFAIK, there's no way to predict if you will have vibrations or not. Some do, some don't and every truck is different. Those that lift less in height generally have less vibrations but that's not completely accurate either.

Switching in to 4WD changes the load on the entire driveline and in my case, was a clue that one specifc vibration at 10-25mph was the result of the front diff angles, position, and mounting bolt torque. I was able to demonstrate no low speed vibes before a diff drop then low speed vibes with a diff drop. Once I removed the diff drop, the vibes were still there, telling me something had changed. In my case, the act of installing the Diff Drop and not retorqueing caused a slight Front Diff shift in position. The Diff drop insturctions said torque to 70Ft/lbs if I recall and that's not enough. My Tacoma manual says 101 FT/Lbs. I used a pry bar and about 110FT/lbs of torque on the front diff bolts. That cured the 10-25mph vibe completely and took me back to happiness.

So yes, it confuses me too. Multiple sources, multiple cures and many possibilites.

 

anyone with driveline vibes...try this and see if it helps you out!

http://www.tacomaworld.com/forum/te...-vibration-fix-write-up-may-work-you-too.html

 

^CB spacers helped me a little, but were not a cure.