Driveline vibration Tsb out

Fat end forward will tilt the pinion down , fat end rear tilts it up

 

The aim with this tsb is to tilt the pinion down, to create more of an angle that more closely matches the ~ 3.5-4* of angle thats on the first u joint out of the transmisison / tcase

 

this^

Every U-joint that operates at an angle creates a vibration.

It creates that vibration because the U-joint cross rotates with the shaft in a circular motion while also moving from front to rear. That rocking back and forth motion as it rotates causes the cross in the U-joint to accelerate and decelerate.

Because the U-joint is connected to the driveshaft and accelerates/decelerates through this full rotation, the driveshaft speeds up and slows down during each revolution. This creates what is called excitation torque.

The U-joint at the other end of the shaft needs to rotate at an equal but opposite angle in relation to the U-joint up front. By using U-joints in pairs and in phase, and the angle between the driveshaft and the equipment at both ends is the same, the acceleration/deceleration cycles tend to cancel each other.

If there is no vibration under normal operating conditions then the angles are correct.
If there is vibration under acceleration, you need to add more downward pinion angle preload
(which is what my Toyota 4 leaf pack with included shims/wedges do).

If the opposite occurs, the vibrations tends to decrease or disappear under acceleration,
you need to reduce the downward angle preload.


In my truck the axle wrap at specific speeds (15-25mph and specific accel rate) made
the angle just far enough out of whack to vibrate. The new wedge preloads the angle in the
opposite direction without introducing more vibes, and, the stiffer springs reduce axle wrap in the first place.

In my case the joint angle (pinion flange angle - propeller shaft angle = joint angle)
was less than .2 degrees so got springs with the 3deg caster wedge.

 

I can't refute this explanation....
But now I'm worried; Can the typical master mechanic at a dealer be expected to know this??

 

I've got a massive vibration on acceleration and took mine in to the dealer yesterday. The tech came up with a -1.5 degree number which puts me in the N/A category. I was sent packing and they weren't willing to do anything with it. The shop manager even had the nerve to tell me that he could make that vibration happen driving ANY vehicle. What a tool. I've had the truck into the dealer three times for different issues now and Toyota hasn't fixed one of them.

 

they probably measured it wrong. Have them put on the 4 leaf pack with the 2 degree wedge.

FYI, there is no catagory that is not covered.... at most you will get a 3 degree wedge... they read the chart wrong. Believe me i literally had to spoon feed the master tech at Ventura Toyota all the details... to the point where i was under my truck with my angle finder on a lift at the DEALER ship showing him how to do it.

 

Are you supposed to read the angles with the truck off the ground ?

 

Heheheh. Nope...

 

Nope

Page 11 of the TSB Circled and bolded note. "Suspension of vehicle MUST be at ride height"

This was a note that the master tech at ventura toyota failed to notice... as i walked in on him my truck in the air on a frame lift suspension fully drooped with him trying to figure out how to measure than angles with my angle finder.

At that point all hope had been lost in them, i showed him the note and asked why on earth would he thing measuring angles at full droop would fix something that occurs at ride height... then negative hope was had when he again failed to order the right parts (leaf springs) after i had highlighted and circled the proper parts to order from page 3 of the tsb.

The whole experience was so full of facepalm it wasnt even funny... I did get a bed mat out of it, which was almost rescinded as the service manager through a hissy fit when i told him i would never walk back in his service department ever again.

 

That's what I thought , guess I misunderstood your initial post

 

The table in the TSB for leaf spring part #'s has a N/A in the last column for less than -.2 degrees on the measurement. Mine measured -1.5 degrees. I don't have a digital angle finder but I do have a standard dial type. I just measured to see what I'd get and on my angle finder I got right at 5 degrees on the shaft and 4 degrees on the pinion flange so with my not so accurate tool, the -1.5 degrees could be correct.

So what happens if they put the 3 degree wedge in and it doesn't fix the vibration? Looks like I'm SOL on getting new leafs either way.

Also, shouldn't they have done the rest of the TSB even though the springs didn't measure out? I hate this dealership.

 

what is the config on your truck, DCLB, DCSB or AC? prerunner or 4x4?

Also that angle you measured referencing the picture below (Red being driveshaft blue being pinion)

Was the angle of the u joint like the top or bottom? (Opening up or opening down)?

 

DCSB 4x4

Hard to tell, but it apprears as though it's like the top pic.

EDIT: the pinion is angled up but is angled a tad lower than the shaft if that makes sense

 

yeah they need to use the wheel lift arms, not frame lift

 

What a difference driving the extra miles to another dealership. Totally different experience. The service manager asked me about my visit to the other dealership and wanted to know what they did. I explained to him what they did and his reply was that they just blew me off. Nothing but good things to say about my experience today. They're ordering parts and will find out if it fixes the vibes. I hope so.

By the way, the dealership I went to today is Camelback Toyota, one of the vendors here on the site.

 

^ I hope yours is fixed. srsly I have a whole new experience driving this thing. it is awesome. I am constantly reminding myself not to baby 10-30 mph to reduce vibes becasue they are gone gone gone. it also seems to shift better along the entire range...it is so smooth now I am unbelievably happy with it.

 

I don't think I'm ever going to get this TSB done. I can never seem to get the time to take my truck in. My company always as me driving somewhere for something and if I even hint of taking the truck to the dealer they want me to have our mechanic look at it to see if he can fix it...

 

Then that would be a positive angle.... If the drive shaft is angled up from the pinion.... It is not a negative. The other dealer was mistaken ... Figures.

Have the dealer order the 4 leaf pack with the 2 degree wedge.

 

Dropped mine off at the dealer on Monday, for a few days. Called and checked with them today... "we are waiting for the transmission mount, so a few days. If that don't work, we'll order the next part." So I asked how long... "not sure." So I guess I'll get my truck back in a week or two

 

For any of you doing this. Go in with the TSB in hand, know what your talking about, and talk to the head mechanic, He will more than likely agree that they should order everything (as well as the angle finder) but the leaf springs before you leave the truck with them.

That away they can install the steering dampener, test (obviously fail), install the transmission mount (doesnt fix it) then measure for the leafs... Steering dampener, test, transmission mount, test should take a max of a half a day. Then you get your truck back, wait for the leafs then drop it off for another half day.

This will save everyone lots of time and frustrations on both parties.


Also note, the chart's for which leaf spring to use for the measured angles are interesting and kind of tricky to read. Make sure you figure that out... easiest way is to start with the truck type, then go to the column that has your angle range that has a part number.

Essentially there are two different angle range groups... one for the DCLB and one for the DCSB/AC setups... they put them all in the same chart and it makes it a little confusing.