Drive Shaft Vibrations Solved Step-by-Step

I am thinking about doing just that with the drive shaft i have ( double cardan). Might give my truck another chance. Will keep you guys posted.

 

What is the most common fix for the take off/acceleration vibration @ about 10mph? It happens just before the first transmission shift. I have OME 885s with dakars in the rear, I have the OME CB spacer installed, I have tried it without the CB spacer and flipped the CB bracket with no improvement. Should I try a larger CB spacer, add washers to drop it lower? Any suggestions are appreciated

 

Check out the video:

http://www.tacomaworld.com/forum/2nd-gen-tacomas/5806-take-off-shudder.html


Good idea what the CB does during accel

 

Hey TSCOT

On the attached photo you posted awhile back - could you clarify the P/N on the side of the Spicer center yoke. Is it possible to use the existing u joint yokes on the stock drive shafts, and buy the spicer center yoke to fabricate a DC joint?

I wonder if the stock rear drive shaft can be flipped 180 degrees with the slip joint towards the diff, and fabricate a DC joint with spicer components?

thanks

 

Thanks for the info - my truck is a 2011 with 13K miles - if I replace or mod the drive shaft bye-bye warranty. The dealership tells me the vibration/shudder is normal for the truck, TSB has been done. I really like the truck but hate the vibes. Trying to figure out which way to go. Thanks again.

 

bmrfm, it's a Spicer C2-26-309 joint, photo attached. I don't have a clue what you can or cannot do, I just wrote a check at the local driveline shop, sorry. It also has some numbers on the opposite side, may or may not be important. They read: 6F-20, 227, and D3 in three separate locations on the side opposite the part number.

And as is evident by PSUTaco85's driveshaft, looks like darn near anything is possible! I forgot about that 4Runner shaft honestly. That's what I get for trying to oversimplify my one-piece two-piece red-piece blue-piece driveshaft 101 explanation!

 

TSCOT

Thanks for the details - I'll check it out a little more. I already spent $800+ replacing the Dunlop tires with decent michelins, trying to minimize the pain. My wife thinks I'm a nut job at this point, spending way too much time on truck vibes.

 

BigHeadTaco, I noticed you haven't had much response, I'll take a try at your issue. Usually low speed vibes (20-30 mph) are CB issues, as evident in video posted by bmrfm. However, take-off vibes are usually rear axle wrap. That posted video is awesome. Stick your mouse cursor right on the upper edge of the driveshaft, at the lower left side of the screen, then press play. You'll notice at first that the driveshaft moves gravity up, as the driver attempts to accelerate with the brake on. That's the transmission side putting torque on the driveline, twisting it gravity up at the carrier bearing joint. Then, when the driver releases the brakes and accelerates, notice that the driveshaft moves gravity down (I used my mouse cursor on the edge of the driveshaft as a stationary marker, then watched as the shaft moved around relative to my mouse cursor). The shaft moves down upon acceleration because the opposite end of that second shaft, down by the rear diff, is moving up with axle wrap, which forces the carrier bearing end of the shaft down.

Now, here's the trick: we're trying to balance the transmission upward forces with the axle wrap downward forces, to get that carrier bearing joint to float freely and perfectly aligned in it's rubber mountings. Otherwise, vibes. Uh..... good luck with that, right? No wonder we have vibe issues, right? I cannot emphasize enough the value of a handful of washers, as we're truly talking about very small adjustments to balance opposing forces. Pain in the butt, yet potentially possible.

How do we achieve this balance? Can't change the trans output angle really, so we mess with CB spacers and leaf spring shims. BigHeadTaco, you already have CB spacers, but with those dakars, have you approached the leaf shim side of things? Sounds like you need to drop the front of your pinion just a tad, 1.5deg shim fat end forward, to account for axle wrap.

 

I have a two piece DS with a double cardan after the carrier bearing. Measures 67 3/8 inches

 

Tscot, thanks for the response. Last night I went to lowe's bought longer CB bolts and washers. I left the OME CB drop and added large circular washers as well. The vibration has decreased, I would say 75-80%, additionally I re torqued my u bolts to 100. I would say my total CB drop is now approx. 3/4". I did not have time to get it perfect as I am leaving on a 300 mile road trip.

 

Tscot I posted a while back and hadn't been able follow up, so I wanted to post my findings.

Truck is a 2011 DCLB 4x4 full OME 885 w/ dakars

My best configuration to this point had been:
1. No axle shims
2. OME CB drop

In this state I had a 5-10mph vibration.

This left me with the following measurements
TC 1st Shaft 2nd shaft Pinion
0.0 3.7 down 4.4 down 1.4 up

Dropping the CB any further or shimming the pinion down to or past 0 creates a 20-40mph and a 60mph+ vibration.
Greasing the u-joints did not help.
Greasing the slip yoke greatly helped with the 5-10mph vibe initially. The yoke was nearly dry.

I've been playing with this for about a month. Today I called the dealer and got to measure a matching new truck and this is what I found.

The new truck
TC 1st Shaft 2nd shaft Pinion
0.0 3.3 down 3.6 down 1.9 up

I'm going to move the pinion the other direction (0.5 degree at a time and reship the CB) and see what happens, and I'll post my suspicions if they prove true.

 

I have a 2 piece drive shaft with double cardan after the carrier bearing for sale. Fits double cab short Tacoma 2nd gen. Total length 67.5 inches

 

I have the low speed vibes. Threw 600# of cement in the rear and vibes vanished. I know somewhere in this 16 page thread someone mentioned 'throwing weight in the back to see if vibes went away', but now can't remember what that was supposed to mean/signify. Can someone relate? Thanks.

 

tscot is the expert, but i would imagine by weighing down the bed youd be lessening the difference in angle of the carrier bearing. meaning your rear shaft would be coming in to the front shaft at a more shallow angle than in an unloaded bed. and if this is the correct dissection, you should be able to shim that CB down to make it similar to what it was when the load was on it.

 

Already have the OME CB spacer. Thought I might have to keep on shimmin'...

 

Denk, dmeko0 has it right. Weight in the truck compresses your suspension, making the driveline angles shallower. Shim that CB more. See attached pdf.

This is of course ignoring the obvious loose bolt syndrome. My truck skates like a dream down the road with a full load in the back. Dog is happier, girlfriend is prettier, annoying rattle behind my glove compartment goes away. Adding weight tends to make loose suspension parts less noisy and vibe free. I would definitely crawl under there and start checking some torque values on shock mounts, leaf u-bolts, that carrier bearing cross member, and your trans / txfr case mounts. Also check tire inflation for over-inflation. If you've lifted, your new suspension might be too stiff for an empty load and you're pogo-ing down the road on stiff-legged suspension. Letting a little air out of the tires helps with that (not a clue what you're running, but 40psi would be more comfortable than 85psi).

 

Osugoose, I've been playing with your measurements on autoCAD. I would originally say to drop your carrier bearing another 1/8", and start shimming your pinion downward. HOWEVER, the theory is shifting a bit lately, and your measurements are most helpful.

Now I'm leaning toward aligning the two shafts in as nearly a straight line as possible, and tilting that rear pinion GRAVITY UP to within a single degree DOWN off the rear shaft. Uh, yeah, makes perfect sense, sure it does, uh huh. See attached pdf, and use the zoom function to take a closer look at the areas pointed out in red.

It actually does make sense, if you sacrifice your save-the-u-joints theory and go for backyard-mechanics-cuz-it-works reality. We can't change the front output angle, so drop that carrier bearing until the two shafts are as close to a straight line as possible, then rotate your pinion to point just slightly down from the second shaft (which is gravity up from bubble level, but rotated down from a perfect perpendicular angle).

My views have changed the more I get experience with those pesky prerunners. They all seem to follow the above pattern, and more so, most dealer 4x4 lifts I've seen follow that pattern as well. Third party lifts tend to go with the original solution, pinion gravity down, but I think that's because we spend more time tweaking to get it right, rather than the dealer going for the quick fix and planning on selling us u-joints later. Technically every bump we hit is going to lube those joints as the angle changes, so I'll shut up on that rant and shift to the quick fix.

For theory test, I changed my truck to front and rear shafts off by 0.2deg of each other (second shaft down from first), and rear pinion 1deg down from rear shaft (gravity up but rear shaft down), and reinstalled the factory driveline (took out double cardan, put back in factory driveline), and truck felt fine for a few days test driving. Put back in double cardan, felt fine still. Changed rear pinion to gravity down 2deg double cardan, still felt fine. Changed rear pinion to 4deg down double cardan, high speed vibes, too much for even the double cardan to handle evidently. Put factory driveline in, low and high speed vibes. Brought rear pinion back to 2deg down with factory shaft, slight high speed vibe. Back to 2deg down with double cardan, silky smooth, left it there.

 

TscotR214,

I'm still working through this and I get you a writeup as I figure out how to write it down. Just wanted to make sure you knew I not forgetting.

Edit: I will give you a brief rundown though.

My first theory was toyota followed the Spicer Diagram 9, but said screw it the 1.0-1.5 first shaft angle. This would give you the flexibility of 0.9 to 1.9 degree of axle wrap during operation with an ideal wrap angle of 1.4. (I'm not sure what the design wrap for my dakars, but through my testing I think the average wrap is around 0.7 to 0.9)

I haven't finished going all the possible pinion angles and stepping through the cb shimming. Even with flipping the cb and no shims I can only get my first shaft as high as 0.8 degree down.

All this is pure speculation as I haven't completely solved my take off shudder, but in testing I have been able to greatly reduce it (I'm a 100% solution kinida guy, and I won't be happy till my vibes are gone). I'll let you know what I find.