Just can't figure this one out. Vibration at speed.

Rot Box

Diesel and Dust
Supporting Member
Location
Smithfield Utah
I've been having a rear end vibration in my Hilux ever since I swapped in 5.29 gears in November. It has annoyed me beyond belief as I have seriously spent an uncountable amount of time trying to figure out this--what should be a--no brainer problem :(

Mega huge long story short: I now have a ballanced 120 wall rear CV drive shaft (third shaft trying solve problem), a brand new professionally set up Yukon 5.29 gear set (second one trying to solve problem). rear pinion angle of 3 degrees if I'm measuring it right (Pretty sure I am). I STILL have a vibration between 58 and 70 MPH. It's a vvrrrrommmmm.. vvrrrrommmmm.. vvrrrommm.. type of thing. Any ideas?

I have tried pulling the drive shaft apart and aligning the yokes in the two different ways with little success. I have also rotated my tires and had them ballanced so that variable is out. My last guess is the thick wall shaft or just bad luck plain and simple :-\ anyone else have problems with a thicker wall drive shaft at higher speeds?

Any ideas would be greatly appreciated! Thanks,

Andrew
 

notajeep

Just me
Location
Logan
Remove the rear shaft, drive, and see if you can isolate (SP) your vibes to the rear end or the shaft.
Second, lets talk about tire balancing. You can bolt a 2x4 to one side of the tire and add enough weight to the other side and you will have a perfectly balanced tire that will still ride like a 30 year old toyota.
Try having your tires "road force" balanced. I know a place, call me if you want to try it.
 

Rot Box

Diesel and Dust
Supporting Member
Location
Smithfield Utah
Remove the rear shaft, drive, and see if you can isolate (SP) your vibes to the rear end or the shaft.
Second, lets talk about tire balancing. You can bolt a 2x4 to one side of the tire and add enough weight to the other side and you will have a perfectly balanced tire that will still ride like a 30 year old toyota.
Try having your tires "road force" balanced. I know a place, call me if you want to try it.

I would remove the rear and test is in front wheel drive only, but I went ahead and took a second mortgage on a Tom Woods front shaft and its good for about 10mph MAX! So unless I pull it with something that's out of the question :(

This is not the typical 30 year old beater POS Rot Box Toyota vibration. I'm very familiar with that one unfortunatly this is something far more annoying :D

I'm convinced it is not the tires, but I'm desperate at this point. Perhaps I will call you in the morning :D
 

Rot Box

Diesel and Dust
Supporting Member
Location
Smithfield Utah
What's up with the Woody? I have a woody's front and rear in my 4runner and they are both great?

))--SLIVER-->

Tom builds awesome shafts no doubt, but I went a route that I wish I wouldn't have with this one. The big problems are the two high angle offset U-joints and 13 inch slip AG splines. Back then I needed a drive shaft with a ton of flex and durability. Unfortunatly that's all its good for :( Looking back I must have been on crack to have paid as much as I did for something I could have built in my garage.

That is the front shaft though. My vibration is coming from the rear end in case there is any confusion...
 

Bart

Registered User
Location
Arm Utah
I have one of Tom's offset joints on my front drive line. I'm only good to about 25 mph. It really sucks. So bad that I'm thinking of running selectable hubs so I can unlock them and take the front out.
 

rollover

Well-Known Member
Location
Holladay
Since you've covered drivline/tire balance maybe check for a cracked flywheel? I had an astro that had a problem like this.

Just a thought.
 

SLC97SR5

IDIesel
Location
Davis County
What about rear axle bearings? When I swapped axles I pried off the bearing cover and pumped it full of grease.

Are the gears in good shape...not broken? My 4Runner had a gnarly vibration from 55+ that ended up being 4 broken teeth on the ring gear.

You are using the lonnnnnggggg 1 piece drive shaft right? No carrier bearing?
 

Rot Box

Diesel and Dust
Supporting Member
Location
Smithfield Utah
Thanks for all the reply's! I finally was able to pull it in the shop for more--I have no life and spend my saturday night--wrenching :)

What about rear axle bearings? When I swapped axles I pried off the bearing cover and pumped it full of grease.

Are the gears in good shape...not broken? My 4Runner had a gnarly vibration from 55+ that ended up being 4 broken teeth on the ring gear.

You are using the lonnnnnggggg 1 piece drive shaft right? No carrier bearing?

No carrier bearing, but it is a shortbed with a single case. It is not much longer than the stock one--maybe 2 inches max. Also the gears are literally brand new so I really hope there is no problems with the teeth.

high angle joint in the CV perhaps? or a broken CV?

It all checks out good :-\

Take your phone off vibrate!!

I'm trying to solve one vibration problem at a time here! sheeeshh :D

Add a CV to the rear drive line.

It has a CV that is in good shape :-\


Okay I'm still pissed and i now know that it's not the tires... for sure.

I (again :rolleyes:) pulled my rear leafs apart and added some shims to point the pinion up a little more. Prior to this I measured it at 3 degrees, but it just looked too low compared to everything else in the driveway...

With these little "tweeks" it now is a quick vroom. vroom. vroom. from 60-70mph.

I just picked up an amazing ATK dirtbike to replace my worthles KTM, and I'm so happy with it I may bag the whole 4x4 thing this summer and get back to riding :ugh: :D
 

jeep-N-montero

Formerly black_ZJ
Location
Bountiful
Check ALL of your bushings and sway bars if you have them. I know it sounds weird, but I had a similar noise at speed and it ended up being a loose front sway bar bushing/bolt.
 

kowe69

wannabe
I noticed that you said your rear pinion is set at three degrees. A CV (double cardan joint) shaft needs an angle as close to 0 as possible at the pinion. A normal drive line with a single joint at each end needs to have equal but opposite angles at both the t-case and pinion in order to be in phase. But the two joints that make up the CV do this by themselves so the single rear joint needs to be at 0. The reason this started when you changed gears is because you are now running the drive line at a different RPM for a given speed. Your drive line may never have reached this RPM previously. I would get some high quality steel shims to bring your pinion angle to 0 and go drive it. I'll bet it will take care of it.
 

DaveB

Long Jeep Fan
Location
Holladay, Utah
You don't want to set it at 0 degrees on the rear ujoint. It needs 1-2 degrees down from 0 or the needles in the ujoint won't turn properly.
 

Rot Box

Diesel and Dust
Supporting Member
Location
Smithfield Utah
I noticed that you said your rear pinion is set at three degrees. A CV (double cardan joint) shaft needs an angle as close to 0 as possible at the pinion. A normal drive line with a single joint at each end needs to have equal but opposite angles at both the t-case and pinion in order to be in phase. But the two joints that make up the CV do this by themselves so the single rear joint needs to be at 0. The reason this started when you changed gears is because you are now running the drive line at a different RPM for a given speed. Your drive line may never have reached this RPM previously. I would get some high quality steel shims to bring your pinion angle to 0 and go drive it. I'll bet it will take care of it.


Excellent! That is what I was looking for. I swear i'm the only Toyota guy in the world that has ever had this much trouble with a rear drive! :(

Before the gear swap--burried in the throttle--I could only pull about 3200K driving 75mph down the freeway now I still can only pull 3200K I just have to deal with going slower. I figure I dropped around 10mph but I'm still in 5th, and at 3200 rpms the driveshaft speed should be the same either way... Right?

Anyway last night I swapped some shims around, and I found that if I point my pinion up to where the drive shaft is almost in line with the pinion shaft I have the best luck.

Now for the zero degree thing. If I take a level and put it on my pinion flange should the bubble center and show the flange as being level--or at basically zero degrees? Or should zero degrees the angle where the driveshaft meets the pinion? This is a newb question for sure :rolleyes:
 

XJEEPER

Well-Known Member
Location
Highland Springs
You will not likely measure 0 on the pinion flange, this angle is 1/2 of your formula, you are looking for the difference between the pinion and driveline angles, relative to 90*.

Measure the pinion angle relative to 90 degrees on a flat surface....(not intimately familiar with toy diffs, but on a D44, there are flat spots where a case spread can be installed, on either side of the diff cover.)
Now measure the driveline angle , relative to 90 degrees. The difference between the two will give you your overall pinion angle, relative to driveline angle. (Example: Pinion measures-87* driveline measured 84*=3* difference.)

A 0 degree difference at speed is said to be perfect when running a double cardan driveline (commonly called a "CV"), you need to compensate for torque induced pinion lift, so the pinion needs to point down 1-2 degrees, relative to the driveline angle at rest. When throttle is applied, the pinion will rise and the driveline/pinion angle will be near 0, which should net you vibe free results. As you've found, shims are the easiest way to tune on a leaf sprung rig.
 

Rot Box

Diesel and Dust
Supporting Member
Location
Smithfield Utah
you are looking for the difference between the pinion and driveline angles, relative to 90*.

Okay great thanks! Now it makes sense that when I shimmed the pinnion upwards it ran much better. I can look at it and tell that I am still off a little, but tonight I'll grab some measuring tools from work and try to fine tune it. This is good news :D
 

kowe69

wannabe
Your on the right track for sure. To put it in simple terms, you want to point the pinion at the transfer-case output. Harbor freight has a great little angle meter I bought to do mine. HERE
 
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kowe69

wannabe
You don't want to set it at 0 degrees on the rear ujoint. It needs 1-2 degrees down from 0 or the needles in the ujoint won't turn properly.

With the exception of some custom rigs of coarse, most but maybe not all manufactures offset the pinion right, left or up of down of the transfer-case or transmission output in order to keep the u-joint needle bearings moving. So yes, in the end a difference of 1 degree or so in any direction would be ideal. But 3 degrees is too much.
 
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