Front DC drive shaft vibration:

[ShottsUZJ100]

UPDATE:

I took the D/C front shaft out of the LX. I'll send that to Slee for inspection.

Meanwhile, we slapped the front stock shaft from our '93 into the LX. The U-joints felt good and consistent though the '93 has 165K on it so some wear to those U-joints must exist. When we drive the '93 every now and then we get some slack.

The test drive of the LX? 95% of the vibration is GONE with the '93 stock shaft in the LX! What's left though is a quick GRRR sound every time you go on and off the gas. Plus, some vibration does exist upon deceleration though it's slight. Also at a few speeds on decel there is some slight GRRR sound.

PLEASE KEEP IN MIND we still have the rear shaft out. It's awaiting another u-joint. Having it in might effect or reduce the current sounds.

MY QUESTION: So how do we end this? My gut? We never needed a D/C front shaft. We lifted the LX and vibration hit. The rear shaft had a bad U-joint. Maybe the front did too though we pitched it becuase we were told we'd need the D/C shaft. Keep in mind we added another 20mm lift to help out the D/C shaft which didn't work.

My guess: Remove that added 20mm lift that didn't help anyhow. This should improve the operation of a stock shaft even more. Throw in the rear shaft and balance via upper rear control adjusts. If all works I'll buy a used shaft to throw back in my '93 for the one I robbed.

WHAT AM I MISSING? Probably plenty?

 

[-Spike-]

Lesson: Never throw away anything. I had to learn that one the hard way too. Several times, as a matter of fact.

Edit to add: Buy a bunch of new u-joints.

-Spike

 

[landtank]

Sounds about right. If you took the time to measure your front pinion angle you'd probably find that you're somewhere between what is needed for either shaft but favoring the stock shaft some.

I still could use a good side view of that front diff at the pinion angle. That would go a long way in understanding how that axle is interacting with the drive shaft. So pull that front right tire off and snap one just over the top of the leading arm right next to the rotor.

 

[Romer]

I had to replace the U Joints on both shafts. Make sure they use Toyota OEM. Also make sure they balance it. You problem could be partially a balance problem. While they have the shaft ask them to separate the shafts, clean out all the old grease and regrease the spiline by hand.

Also, make sure they know the front drive shaft is suppose to be out of phase before they balance it.

I agree you probably didn't need the CV shaft. I had to do all the above to make my problem go away, 6 months later, still quiet.

Edit: Corrected post, incorrectly stated rear drive shaft should be out of phase when its the front

 

[Tools R Us]

...Also, make sure they know the Rear drive shaft is suppose to be out of phase before they balamce it...

The front driveshaft is suppose to be out of phase.:whoops: But mine runs smoother in phase.

 

[Romer]

The front driveshaft is suppose to be out of phase.:whoops: But mine runs smoother in phase.

The rear is suppose to be in phase and the front out of Phase

The shafts are similar except the Rear is longer and is in phase,

The Front Shaft is "out of Phase", note the ears on the front yoke and rear yoke are 90 deg offset

Edit: Stupidly had the in and out of phase backwards. Knew it, but typed wrong.

 

[Rich]

In the picture above the top shaft is depicted out of phase and the lower shaft is depicted in phase.

 

[Tools R Us]

Phase:

We say that 2 u-joints are in-phase if they are fitted to yokes that are fixed on the same shaft, such that the 2 opposing bearing caps in the u-joint that are held captive by the yoke on the shaft (the inboard yoke's u-joint caps) are both in the same orientation.

From;

http://www.pirate4x4.com/tech/billavista/PR-shaft/index2.html

The front shaft is 90 deg out of phase from the factory, it's the only vehicle that I can think of that is that way, very unique. Also the broken back geometry is unique.

 

[Romer]

Dooohhhh, You guys are correct. Good thing I included the picture. I pasted that from something I was working on late at night for the FAQ, not there yet. Obvuiously, it was too late in the evening.

I knew that because I had done both my shafts 6 months ago.

I corrected my above post, great link. Thanks.

 

[ShottsUZJ100]

OK EXPERTS....I HAVE ANGLE MEASUREMENTS!

I went to a local expert with tools and learned a lot. Whiteboard drawings sure helped too. Here's what we found out. Now, what do I do next? THANKS!

T/Case front flange is UP 3.5* and T/Case rear flange is DOWN 3.5*
(Is this normal? I'd think they'd be level? His garage was.)

FRONT MEASUREMENT:

T/Case 3.5* UP
Front Pinion 6.5* UP
Slope 9*
So the difference angle is 2.5* which should be just in the working range of the D/C front shaft. (??) He said there's no way a stock shaft would work...we removed it.

He inspected the new DC shaft and believes it is bad. He showed how it is rough in places and that it makes some noise when turning by hand. We did not re-lube it because it's new and it came with problems (noise/vibration) out of the box. I sent it back to Slee today. If it is bad a new one will be sent back.

REAR MEASUREMENT:

T/Case 3.5* DOWN
Rear pinion was 2* UP...we adjusted to 3.5* UP and are driving this way now. It rides smoothly with the rear shaft in only.

So, what should I do next?

A. Put in D/C shaft when a good one returns and see how it goes?
B. Not wait for that. Get working on another solution now because of front geometry (though it might not need more work/lift/whatever)?
C. ?
D. ?

 

[Romer]

So what does it do when you drive it without the front shaft? Use the CDL switch John. Is there any noise?

Do you still have the old front shaft? You might put it in and try it. That would take you about 10 minutes.

 

[landtank]

So you have 2.5* angularity at the front diff. Which dirrection would you have to move the axle to correct this, more of less caster correction?

 

[Romer]

Done all that testing already.

Your post above says with front shaft in and rear out or did I miss it in another thread.

 

[landtank]

I'd need to angle the pinion UP another 2.5*

Well that would mean that you need less correction. This does seem strange. I still would like to see that side shot of the diff from the driverside to be sure. But if this is the case then you would want to remove Slee's plates and press in bushings. There was another member recently that his pinion alignment looked like what you are describing to me here.

Pull the DS front tire and get a nice straight on pic of your front diff from just rear of the rotor and above the arm, please.

 

[ShottsUZJ100]

So what does it do when you drive it without the front shaft? Use the CDL switch John. Is there any noise?

It's fine with only the rear shaft.

Do you still have the old front shaft? You might put it in and try it. That would take you about 10 minutes.

We've done this before and posted on it. Nope....neither front shaft worked out. I think the D/C is bad.

 

[Romer]

John, my question is what does it do when you drive it WITHOUT the front shaft. Rear shaft only

 

[Beowulf]

Pull the DS front tire and get a nice straight on pic of your front diff from just rear of the rotor and above the arm, please.

You've asked for this at least 3 times over the past month and haven't gotten the pics, yet you are still trying to help him figure out what is wrong. You are a LOT more patient with this than I would be.

-B-

 

[ShottsUZJ100]

John, my question is what does it do when you drive it WITHOUT the front shaft. Rear shaft only

It's fine.

"T/Case 3.5* DOWN
Rear pinion was 2* UP...we adjusted to 3.5* UP and are driving this way now. It rides smoothly with the rear shaft in only."

 

[ShottsUZJ100]

You've asked for this at least 3 times over the past month and haven't gotten the pics, yet you are still trying to help him figure out what is wrong. You are a LOT more patient with this than I would be.

-B-

Easier said then done. I myself cannot physically do it. I'd have to be at my mechanics 24/7 to get the pic and I do work. You're right. Good thing some are extra patient.

 

[landtank]

With hopes of clarification so I don't send you down the wrong road.

Does the pinion seem to point below the T-case flange or above it?