Just fixed driveline vibration!!!For free!

Your first shaft and pinion angles should not be the same. If that is true then your Tcase Ujoint is the one vibrating. It's operating at 5 degrees and nothing is canceling it. Your Tcase output and your pinion should be the same. You shimmed your axle right? Take the shims out. Check the pinion/ Tcase angle. Then drop your carrier until you have about one degree of difference between the 2 shafts. They should appear almost straight.

 

I will try that tomorrow. ^ thanks a bunch badger.

I think the shim actually helped some.. I got the CB droped only about 1/4".. and the take off vibe is almost gone.. I will try nothing on the CB and see if the angles are better.. If that doesnt do the trick, then I will ditch the shims...

 

sup incase i lift and have vibs.

 

Well today I took out the 2* shims, and started from scratch. I ended up only dropping the CB about 3/8" to straighten the drive shaft, making the 2 shaft angles about the same.. This is the best it has been and is going to get i geuss.
I also made sure the shafts were straight inline with one another..

Vibe is pretty much not even there..

 

doesn anyone know if spacing the carrier bearing on a non lifted dc will help with the vibes?

 

It will if that's the problem. There are lots of things that could cause a vibration and every truck is a little different.

 

I'd like to post my angles and see if someone can interpret them for me. I have a Maxtrac Spindle lift w/Bilstein 5100s set at .85, and an Allpro Expo pack in the rear. I will caveat my measurements with I'm using a Lowe's Digital Angle Finder which was a little different, and I had to incorporate a level as well, which might induce some error and force me to buy what the OP used.

My First Shaft Angle is 6.4 degrees down.
My Second Shaft Angle is 10.9 degrees down.
My Differential Input Angle...taken by zeroing while on the Second Shaft, is 9.6 degrees.

These measurements are from a true level plane, as I did not take my transfer case angle and then zero while on the transfer case. I measured it after the fact and it looks like it's 7.8 degrees down? That being said, it would seem that my first shaft angle is actually +1.4 degrees up from my transfer case? Does this seem right. I'm a total noob at driveshaft measuring, but I followed the instructions as best as I could. Any help or guidance is appreciated!

 

I haven't looked under a prerunner so I don't know what's going on under there. The only useful information I can get from your numbers is that the 2nd joint is operating at 4.5 degrees. The others sound suspect. It may be tough with your gauge, but you need measurements with the gauge zeroed on the Tcase. That gives you the operating angle of the first joint which you need to decide what to do next. The access cab and double cab short box 4x4s have about a 5 degree operating angle (down) on the first joint with the carrier unshimmed.

There are 3 relationships that you need to establish:

1. Transmission output angle to pinion angle relationship (zero on TC > measure the pinion).
2. 2nd joint operating angle (you did that OK, but better to zero on one and measure the other)
3. 1st joint operating angle (zero on TC case > measure the first shaft

 

Okay so I used 21st Century technology and purchased an APP on my Iphone to make it a Digital Level...HAH...for .99, worked like a charm. Using the worksheet on page 2:

Transfer Case output was 3.7 degrees...then I zeroed off of that.

First Shaft Angle is 3.8 degrees, Second Shaft Angle is 7.9 degrees.

Differential Input Angle is 7.6 degrees.

Would you agree that I need about a 4 degree shim IOT match my differential angle with my TC output angle? I'm sure my Expo Pack hasn't settled yet since it's only been on for a couple days, would buying a 3 degree be more prudent, or perhaps a 3.5 degree if Summit has one to account for possible sag?

Obviously the Carrier Bearing needs to go down IOT make the 1st and 2nd shaft values closer together, any recommendations on how much? I'm thinking washers would probably work?

BTW, I appreciate your knowledge, I can tell you have ample in regards to drivelines!

 

A phone app Good lord, what next. Well, as long as the measurements are repeatable it should be fine. The numbers sound reasonable except that the pinion sounds off. So you zeroed on the Tcase and then the pinion was 7.6?? You didn't happen to turn the phone around when you did that, did you? I ask because your tcase is at 3.7. Flip it around and you get additive angles. 3.7 x 2 = 7.4 You have to keep the "phone" in the same orientation from TC to pinion. You get what I'm saying?

If you did flip the "phone", then your Tcase/Pinion angle is actually zero, which is perfect. Now you just need to drop the CB, and I would guess about 5/8" inch would get you where you need to be. You can see what that does and fine tune from there. You want the second shaft just maybe .5 degrees more (down) than the first shaft. In other words the two should be almost straight inline.

If you did not flip the phone, I'm stumped. I haven't seen a pinion that far off and don't know why it would be.

 

Just curious, how much lift did you net on the expo pack?

I'm also dealing with a slight take off shutter. I'm only lifted about 2" in the rear so I came up with about 2 deg at the pinion. With about 5 deg at the TC the only way for me to equal them out is shim the axel down or lift it more right? The CB or middle joint is about 0.7 deg without any CB shim.
I took some measurements on a stock prerunner for reference. I showed about 4 deg at the CB and zero at the pinion so in stock form it appears that the front and middle U joints cancel each other and the pinion is zero. Does that sound right?

 

Damn dude you are spot on! I was having to rotate the phone 180 degree to place it on the oppositve side of the differential since it's flatest on the starboard side on my Tacoma, which was negating the "zero" I had from the TC. So all things being equal, they are zero, I bought a variety of Grade 8 washers and thicknesses and I'm going to square away the driveshaft angles and see how it works. Much appreciation my friend, there's a whole lot of win going on today!

 

You supplied me with accurate numbers so things were clear for me to see,... even when you screwed up . I hope it works out for you. Make sure when you bolt up the CB that you get it aligned side to side too.

 

Posted this in the wrong thread before...
---

Today I moved from major vibes to minor vibes by flipping the CB. This weekend I'm thinking I'll add the 2 degree shims to make the rear diff angle 0 degrees.

Here's where I am now:


If I install my 2 degree shims then I'll still have issues since the TC angle and second shaft angle are not opposite. I guess I'll add the CB drop too to see how that works out. Any ideas?

EDIT: the process I used for measuring angles was: zero the angle finder on the TC. measure 1st shaft angle. measure 2nd shaft angle. zero angle finder on rear diff. measure rear shaft angle.

EDIT2: on second thought. If I just lower the CB enough to get it from 2.8 (4.9 - 2.1) to 0 degrees, then perhaps the TC and rear diff angles will cancel each other out, as long as it doesn't have to be lowered too much causing the TC angle to go over 3.5 degrees.

 

Actually, raising the truck has little effect on the pinion angle. In fact many lifts do absolutely nothing. MRW has no ill effect at the pinion at all on his truck. I didn't on mine either. If the lifting springs and other parts maintain the angle, it won't matter. So what I'm saying is that lifting to correct angles is not a good strategy.

So the pinion is off 2 degrees from the TC, or is it 3? I would double check that just to make sure. Zero on the TC and measure the pinion. Don't flip the gauge . Is the pinion up or down? Bottom line is, if you do have 2-3 degrees of difference you'll have to shim the rear axle. You can't have the pinion and the TC out of alignment.

On a taco the first and third joint cancel. The middle is at zero. You get there by aligning the pinion/TC and THEN dropping the CB to bring the center joint to near zero. That geometry puts the first and third joint at the same operating angle and those 2 cancel. Joint 2 is near zero and requires no canceling. No vibration.

The reason the taco is so sensitive to lift is because the operating angle at joint 1 is fixed by the carrier bearing. Only the operating angle of joint 2 and 3 change. That means the 1st and 3rd don't cancel anymore, AND now the 2nd is not at zero either. That happens even if the pinion is not rotated. As long as the pinion isn't rotated by the lift, the CB drop will fix the operating angles of both 2 and 3 at the same time. If the pinion is rotated, you have to fix that first. No way around that.

That's about as well as I can explain it without graphics. You can model it and see the geometry at work. Maybe someone smarter than me can do that and post it.

 

We have a winner Joint 1 and 3 are only .1 degree apart if I read that right. You need about a 3/8" carrier drop, and that is it. The last thing you want is an axle shim.

You need to redo this though first:

The part I marked in red is wrong. That relationship doesn't matter. You must zero on the TC and measure the pinion (or visa versa). You should get zero. If that number is not zero, then you have to shim the rear axle. You need to be very careful taking these measuements because we aren't talking about huge angles here!

Just as a side note: Of the trucks that I have helped with this, only a couple have needed an axle shim. It appears to me that it is actually rare. Unfortunately you have to check it, because it can affect any correction at the carrier if it is off. The one affects the other.

 

hmmm. So Erll's instructions on page 2 of this thread (instructions with pics) are not correct? Step 4 and 5 state to re-zero the angle finder on the rear shaft to measure the rear diff angle...

you're saying I measure the rear diff angle by zeroing the angle finder on the TC.

Also, the pinion is the rear diff right? And why do other guides state that only 2 angles need to add up to 0? Not necessarily TC and rear diff angles...

 

Yesterday i finally fixed my take off shudder by first spining the CB 180* and then installed the beefedtaco bracket ive had. Worked like a charm!
His bracket dropped it about 1-1/2" and it sure beffeed up the support as well..
So now all my angles and good, and I cant even feel a take off vibe. Is pretty much gone. soo happy!!!

its still there, but slightly. checked my angle again, and had a negative angle at the 2nd joint.... Im ganna have to really think about what I need to do...

 

Well based on the measurements I got on the stock prerunner thats not true? On both trucks I got about 5 deg off the TC to 1st shaft. Then on the prerunner I got about 4deg opposite on the CB and about zero at the pinion. On my lifted truck I got 0.7 at the CB and 2 deg at the pinion. Now that its lifted the rear DS is at a steeper angle thus the 2 deg at the pinion and less angle on the CB. I theory the more you lift it the more angle your going to get at the pinion and then at about 2.5" lift the CB is at zero. > more lift and the CB starts to angle down. Just my theory usless someone proves me wrong. This problem is a bear because the way Toyota designed the DL. Lift = PITA

 

KingMoo,
I too noticed this error, and it's what was confusing me. Everywhere I looked it said the Transfer Case angle and the Differential angle both needed to be the same, but I kept reading those instructions and saying WTF? I'm sure he meant it the way we are saying and even though Badger didn't come out and say it before I did it, I did exactly what he said. Zeroed my Angle Finder on the TC, then moved it to the Differential...remembering not to swap sides this time , and it was zero.

Now all I'm doing is going to get longer bolts for the Carrier Bearing tomorrow, stack some Grade 8 big washers on it, rebolt it back up, and get my 1st and 2nd Shaft Angles as close to ZERO as possible...hence essentially simulating a one-piece driveshaft...in my mind at least.

HB Taco,
When I called Allpro, they kept telling me I shouldn't need a shim, something along the lines of their packs are built to take the so-called "angles" into account?! Whether this is correct or not I don't know, but logic states you could build a 3-4" leaf pack with 3-4* of angle in it to compensate. Who knows?