Drive Shaft Vibrations Solved Step-by-Step

Wheels come off, hubs come apart, axles come out, diff comes apart. Diff housing stays in place. Crap load of wiper seals, bushings, bearings. Good luck with that.

 

Anyone who changes gear ratios would have to disassemble the diff. What would be the cost to have a shop do it? Any Toyota techs on here?

 

double post

 

Anyone know how to find out the factory differential gear ratio?
I don't have the owners manual or window sticker , bought it used.

 

It's either 3.91 or 3.73 I think, regular cabs I'm not sure what dictates.

 

Here's my findings

******Disclaimer****** These are just my findings with my measurements, if this doesn’t work for you please don’t rip me, keep in mind every carrier bearing wears differently, and every leaf spring, or add a leaf reacts different in wrap. These are not just set it and it works solutions, you still have to play with things. I’m not putting these out here to prove anyone right or wrong, I’m just trying to help. This may work for you, it may not.

My observations so far,

There are two types of vibrations I’m going to talk about here, take off shutter (7-9 mph), and mid to high speed vibes (16-19mph, 21-25mph, 32-40mph, 53-60mph, 70+mph) and I’ll go through my solutions for each of them.

Stock Tacoma DCLB 4x4

TC 0’d
First Shaft 3.3
Second Shaft 3.7
Pinion 1.9

Using an angle spreadsheet I created, I ran the pinion through a full range of axle wrap, and I got some interesting results. If I applied 1.4 degrees of axle wrap to the stock spring, I get these results:

TC 0’d
First Shaft 3.3
Second Shaft 3.35
Pinion 3.3

Toyota’s stock configuration would put the pinion and the first shaft in a line at 1.4 degrees of wrap, because of spacing, this also put the second shaft in near perfect alignment as well.

From everything I have found, toyota setup the second gen 2-piece shaft as following Spicer’s recommendations....... to a point. This means that the pinion is lined up with the first shaft, not the transfer case. Now the angle of the first shaft is not 1.0-1.5 as Spicer recommends, for my DCLB 4x4 it is 3.3 degrees down of the TC (My DCLB 4x4 has a 28in first shaft). Barring a change in the cross-member height on other vehicles, DCSB 4x4 would have a stock angle of between 3.3 and 3.8.

This is still befuddling me, because now I have a 3.3 degree angle that has no opposing angle.

My theory was this:

Part 1: The first shaft and pinion in an operating alignment takes care of the mid to high speed vibes. This I had reinforced from earlier testing.

Part 2: The low speed shutter comes from the slip shaft binding and releasing in chunks under torque at low shaft rpm. The problem is that the pinion is turning up under axle wrap, and the second shaft is built to compress to absorb this, but at a higher shaft rpm. The problem is that you have two competing forces, and the carrier bearing and crossmember are on the losing end. The shaft wants to extend and the pinion is physically lifting it under the truck. To fix this, the pinion and the second shaft need to be as close to zero as possible. There may also be a moment force acting here causing issues as well (Think of taking a long rod, or better a spring and spinning it. The spring wants to spread and you can see the deformation, your shaft is wanting to the same thing before the u-joints and the shafts can build up enough angular momentum to smooth out.) I have had the hardest time quantifying this and proving its the driving force behind this particular vibe.

From what I can tell this is mostly an issue on non DCSB 4x4 and non ACLB 4x4 trucks. These were the base models that our drivetrains were designed around, prerunners and DCLBs seem to be the ones with this issue. I believe that this is because of a difference in the proportions between the shafts. Using TscotR’s measurements, his second shaft to first shaft ratio is around 1.62:1. My shaft ratio is 1.80:1. This means that my second shaft has even more mass than my first shaft, and the mass of the first shaft is less effective at dampening the forces generated by the second shaft, and the end result is the angular momentums can never effectively cancel out, causing us high and low speed vibes.

Testing:


To test this I turned my shims around and went a half degree at a time, and I got some convincing results. I should state that I lifted with Dakars, and I found their natural pinion angle to be 1.4 degrees pinion up and an wrap angle to be 0.8 to 0.9, much stiffer than the stock springs I had calculated at 1.4 degrees of wrap, which changes the game a little. So I’ve found I have to shim the pinion an additional 0.5 degrees up to replicate the stock characteristics.

For my first test:
Pinion shimmed to 2.4 up
The best results came at stock CB position of 3.3 down, no (absolutely none) mid/high speed vibes. 9mph shudder tolerable but still there.
Stopped
TC 0
1st 3.3 D
2nd 5.2 D
Pinion 2.4 Up

Calculated in operation based on a wrap of 0.9 degrees
TC 0
1st 3.3 D
2nd 5.0
Pinion 3.3 Up

This represents angles of 1.7 degrees at each end of the 2nd shaft. This balances the mid and high speed vibes, but 1.7 I feel is too steep to combat the low shudder.

I repeated in 0.5 degree increments, and my low speed shutter better each time, but unfortunately began to pick up some interesting side effects (more of a feeling looseness to the shaft) this may have been a vibe but I couldn’t tell, but it is most likely due to a growing 1st shaft angle (3.3 to 3.8 to 4.3 as I kept testing). Consistently the operation of the shaft was best with the first shaft and the pinion being at a 0 degrees (in operation, 0.9 at rest) of each other. 3.8 degrees as better but not perfect, 4.3 had almost no low speed shutter but felt very 'loose', this was too far for the second shaft (reverses the pinion angle).

I think the above is a viable solution to stock or add a leaf vehicles with less lift.

I still was not happy with the solution, so I went to a different setup entirely now,

I currently am set up at:
Stopped
TC 0
1st 2.4
2nd 5.3
Pinion 3.9

Calculated in operation
TC 0
1st 2.5
2nd 5.1
Pinion 4.8

This makes the 1st shaft most closely mimic a double cardan joint, with the pinion relatively straight to the 2nd shaft. Now I can happily this seems to have solved all my vibrations to my satisfaction. I can’t seem to feel my low speed shutter (oklahoma roads are so bad it may still be there, but only ever so slightly), I have no mid/high speed vibes, and the shaft feels firm like stock. So overall I’m happy.

 

I am still trying to figure out the problem.it sounds like a rachet when turning the axle .The sound is coming from the differential where the axle goes in . Don't know if they all make that sound.I am driving the truck and the only thing I notice is a humming /slight vibration around 65 mph.What would make the noise in the diff. Would you mind jacking up the drivers side and spin the front wheel to see if you hear a ratcheting sound? I have cell phone video of the noise but could not get attached here .

 

Well gentlemen I finally solved my vibes. I replaced my tacoma with a t4r. Didn't want to but after a recent promotion I now have a daily 60 mile commute so I drive the car and my wife and 2 children needed something with some decent cargo room and more creature comforts so I found a nice 2008 limited 4wd v8 with navi.




I'd like to thank Tscott for all his help and generosity and all the rest of you as we'll. This is by far the best group of people I've never met and I'll continue to be a part of it and as soon as I get a closer location I'll get another tacoma.

I have a shim kit along with some extended leaf bolts and an electronic angle finder (given to me by Tscott and shipped free of charge) to pay forward to someone in need. I'll even pay shipping. Unless Tscott has something else in mind.

 

I just installed Dakar leafs on my taco today. I've had driveline vibes from the start, even after the TSB. Feels smooth as glass now! Will see if it stays that way.

 

Baco...... Noooooooooooooooooooooo! I thought all those really bad dust storms around Lancaster were you out in the desert tearing it up and having a good time! Well fine, we all have to grow up sometime I guess... Beautiful new, nice and safe family ride! Congrats on kid, promo, and car!

bjboucher..... nice ride! I'd be curious to see what a set of 285/70/17's would do, looks like you stayed pretty consistent with your manufacturers with good success.

Osugoose.... I bow down in recognition of excellence! Fantastic analysis! I've been beating my head against my driveway and my knuckles against my air tools trying to figure a mechanical way to actually measure what goes on back there under acceleration, but those images of the car dropping off the jacks in Ferris Bueller keep me from really getting too carried away.... Thank You for a great synopsis!

 

I did the same, added a set Dakar leafs and leaf springs clamps FWD and AFT of the axle. plus torqued my u bolts to 100 ft/LB ( re torqued after 2 weeks or 100 miles) no vibration and ride quality is great.

 

I gave up trying to fix my take off shudder. Tom Woods double cardan came in late yesterday!! Now to find the time to put it on. Saturday for sure, if not sooner.

 

Thanks, just trying to help. I sure hope that this does.

I'm debating setting aside cash from the next paycheck and putting a pack of shims (oh say 0.5s and 2.0s, spc's come in packs of 6) and an angle gauge to send around as a pay it forward and pass it on kinda deal, but I'm not sure of the sustainability of it, or if its worth the shipping to keep it moving.

In the mean time, if someone needs shims (and know what they need) I have some spares in 0.5, 2.0, and even a 4.0. Please measure first. Just PM me and I'll send them your way, free of charge, till they're gone. I even have some spare stock tube I can cut for centering pin spacers. It's not as beefy as what Oz has pics of, but it did the job for me, just let me know how long you need them.

edit: TscotR214, I didn't know your garage backed up to a ravine... very interesting.

 

Just got back from a test drive....take off shudder GONE....20 mph and acceleration vibe GONE.....TACO takes off and accelerates like the wife's Avalon......Worth every penny

 

Nice - what was the total $ for it?

 

$479 delivered for the double cardan...

 

I'm jealous! Is the double cardan greasable while it's on the truck, does the shaft incorporate a slip yoke, and is the joint at the pinion end a standard u-joint?

Last year I contacted Tom Woods and they essentially tried to talk me out of a one-piece with a double cardan; they wanted me to try the least expensive option first, which was a two-piece with a CV joint incorporated somewhere (If I remember correctly). They wanted to send it to me, have me try it, and then send it back to them if it didn't do the trick. After that, they'd then send me the double cardan shaft. I didn't want to go through all that hassle, so I opted to try axle and carrier bearing shim experiments. The shims helped, but I still have a take-off shudder. Therefore, I'm seriously wanting what you went with.

Did Tom Woods try to talk you into different options, or did they simply send you what you asked for?

 

saving this one for the archives once i put my leaf pack in

 

All the u-joints and the slip yoke (yes has one) are greasable with the standard zerts. The section between the two u-joints on the double cardan is going to be tricky. The only time its accessible is when its on top. They sent a special tip to put on the end of your grease gun. Its going to be trial and error the first time. I imagine it taking both hands, both feet, holding something with my teeth and pumping the gun with my elbow....LOL. It will still be worth not having that take off shudder though. And yeah, I went though all the CB drop, flip and axle shim exercises. Still had the shudder and vibe.
I first e-mailed Tom W about what I wanted and requested a price. They sent back that generally the standard shaft with single u-joints on each end worked for trucks lifted 3" or less, but didn't push me that way. That was it and gave me the price for both (only $80 difference) and what measurements they needed. They did say if it didn't fix my problem I could send it back for a refund. I measured, called and told them what I wanted. They built it the next day and put it on UPS. Three business days later it was at my door.

 

PINS, nice to know that the Woods drive shafts have standard zerks on the double cardans! My local shop in San Jose, Ca made my double cardan with some funky needle like grease fittings, takes a grease gun adapter that looks like one of those needles used to inflate a soccer ball. I grease it with every oil change, or should I say, I request the dealer to grease it with every 5k services, then go home and do it myself because they always miss those fittings (they're usually under a layer of grease and dust, flush mount, completely hidden). It involves jacking the rear end to rotate the drive shaft, and yes, it takes several hands, a couple of feet, and lots of elbow joint lubricant (vodka in my case).

Wailua Taco - Kauai rules! Koke'e has some of the slickest mud I've ever driven in. Crunched the heck out of my first two Nissan Pathfinders up there. Fun though! I miss the chili & cornbread at the lodge..... good years those were.

Osugoose - why yes, my garage does indeed back up to a ravine. Ask the tow truck driver who had to pull my Tacoma out of the ravine after I went in trying to pull my Bobcat tractor out of the ravine. Seemed like a good idea at the time....