Rear Wheel Bearing Vibration?

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OregonLC said:
Could be, however there's not much of a lift after 4,000 lbs rests on that axle, and it's been at the same angle for the last six years. I do have adjustable MT links top and bottom in the rear and it did occur to me to clock the nose up a few degrees.
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I hear you but you are kinda running out of options. All this time, you might've been running on that ragged edge of non-vibration/vibration. Worn control arm bushings and/or worn engine/transmission bushings could alter that driveline angle just enough to cause a problem. Poly bushings are not known for their longevity either. :)
 
Yep so applying the handbrake during the worst vibration under power quells it. I'd say the foot brake eliminates 95% of it and the handbrake probably 85% but it seems to definitely isolate it to rear axle movement in the hub assembly.

The only thing I can't explain is how removing the propeller shaft also eliminates it. Power and decel are both what brings it on. That makes me think gears but how would foot brake eliminate gear vibration if there wasn't looseness at the end of the axle? From the perspective of the gears braking is just added load, right? Unless something is moving where it shouldn't that gets guided by brake calipers.

Dealer appointment at Beaverton Toyota on Monday...
 
Bummer. Not rear wheel bearing. Kudos to Beaverton Toyota though for spending the morning troubleshooting and not charging for the extra hours spent.

Tech feels that it's either pinion angle or gear lash inside. With MetalTech adjustable links upper and lower I should be able to pivot the pinion up. Any guidance on what is desirable? I've read that zero angle is actually not great for a spider as it will create a wear spot in a single location. Don't know if this is folklore or real.
 
How do you know if your diff needs to be pointed up? Point is you need to get an angle finder on output and diff flanges and drive shaft to determine working angles to know where you are and where to go.
 
Good point. Looks like I need to do some math first.
 
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Flanges are very close to parallel (maybe 0.5 degrees depending on how you set it on the flange) and shaft is within a 1.5 degrees of flanges. Is the 0.5 degree significant?
 
The 3rd @ .50 degree offset downward should be optimal. That's what you want to shoot for.

With the Toyota 4link set up and poly bushings in the MT control arms there should be very little if any axle wrap (upward movement) on hard acceleration. .50 down from your output flange will compensate for any minor upward movement- and keeps a slight angle to load the spiders.

Another idea , maybe check runout on on the flanges?
 
So ruling out wheel bearings, pinion angle, u-joints, shaft balance, and tires I'm back to thinking about the rear gears. I have no detectable bearing play in the pinion (flange is solid) but wondering about backlash. I get maybe 1/4" rotation at the flange bolt with the wheels on the ground (and a descent clunk between D and R). This seems normal on the 100. Excessive? Trying to think what else inside the third member that could be causing vibration.
 
abuck99 said:
The 3rd @ .50 degree offset downward should be optimal. That's what you want to shoot for.

With the Toyota 4link set up and poly bushings in the MT control arms there should be very little if any axle wrap (upward movement) on hard acceleration. .50 down from your output flange will compensate for any minor upward movement- and keeps a slight angle to load the spiders.

Another idea , maybe check runout on on the flanges?
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The pinion flange was new with the gears and shows no noticeable signs of impact. Could be out I suppose but it would have been out since new if that's the case.
 
Dang- feeling your pain man.

How many miles on the gears? Sometimes things take some time to show up. Where Did you get the gears installed? Can they help consult?

Maybe post up in hardcore and get some wisdom there.

By chance what are the condition of the ebrake bellcranks- nothing sticking in the drum?
 
There are two season on the Nitro gears. So maybe 10-12K miles. Shortly after the vibration started I noticed a leak at the pinion seal. Took it back to a known good gear guy (Dan's Gears in Sherwood) and he checked it out and found the problem to be the pinion seal. Felt the lash and didn't notice anything bad. All he does is gears and he's done multiple ARB/Nitro installs so it's not like he's a newbie.

The belcranks are in good shape, plenty of freedom. If anything the e-brake is too loose. Takes 5-6 clicks to get it to set. And it sets first on the driver side, so there may be something going on in the passenger drum. It's worth checking. Don't feel any drag though.
 
I'm outta ideas. Sounds like Dan's would be a good resource.

I hope for you it's something reasonably simple-low cost to correct.

Keep us posted
 
OregonLC said:
So ruling out wheel bearings, pinion angle, u-joints, shaft balance, and tires I'm back to thinking about the rear gears. I have no detectable bearing play in the pinion (flange is solid) but wondering about backlash. I get maybe 1/4" rotation at the flange bolt with the wheels on the ground (and a descent clunk between D and R). This seems normal on the 100. Excessive? Trying to think what else inside the third member that could be causing vibration.
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This will be hard to kind of do with the center section still in the axle/accurately. If you block the rear tires on one side front and rear on a flat surface, with the rest of the driveline in neutral, there should be hardly any movement (rotation) from the pinion output since the carrier(ring side) should be locked. If that makes sense. You should be able to detect a small amount of backlash spacing between pinion and ring gear. Have you tried drawing the diff fluid to see if anything extra come out?

Another thing you might want to consider is the possibility of a small bend in one of your wheels, not sure what you have access too as far as tools, but I have spent more time than I care discussing tracking down similar issues. A slightly out of round wheel can "balance" on a machine, but upon closer observations depending on the tech doing it or if you have access to a machine, may in fact reveal that the wheel is out of round- not always noticeable or easily diagnosed.

I feel your pain needless to say. Good luck.
 
bwell said:
This will be hard to kind of do with the center section still in the axle/accurately. If you block the rear tires on one side front and rear on a flat surface, with the rest of the driveline in neutral, there should be hardly any movement (rotation) from the pinion output since the carrier(ring side) should be locked. If that makes sense. You should be able to detect a small amount of backlash spacing between pinion and ring gear. Have you tried drawing the diff fluid to see if anything extra come out?

Another thing you might want to consider is the possibility of a small bend in one of your wheels, not sure what you have access too as far as tools, but I have spent more time than I care discussing tracking down similar issues. A slightly out of round wheel can "balance" on a machine, but upon closer observations depending on the tech doing it or if you have access to a machine, may in fact reveal that the wheel is out of round- not always noticeable or easily diagnosed.

I feel your pain needless to say. Good luck.
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*draining diff fluid
 
I run the same wheels and tires on the trailer and swapped both sides (same brand, all <1,000 miles).

With the shaft off I do have rotational play at the pinion flange. Haven't measured but I'd say 1/4" at the flange bolt center. Maybe a bit more than on our stock 04. The pinion/ring backlash may indeed be loose, but once it's snugged up under load would that cause a vibration?

When the pinion seal was replaced he drained the fluid and said it was good with only a thin paste on the magnet.
 
OregonLC said:
I run the same wheels and tires on the trailer and swapped both sides (same brand, all <1,000 miles).

With the shaft off I do have rotational play at the pinion flange. Haven't measured but I'd say 1/4" at the flange bolt center. Maybe a bit more than on our stock 04. The pinion/ring backlash may indeed be loose, but once it's snugged up under load would that cause a vibration?

When the pinion seal was replaced he drained the fluid and said it was good with only a thin paste on the magnet.
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Hmmm. I'm not an expert, but I don't think a little excess backlash would contribute to any sort of vibration, rather potential for other differential issues.
 
I hear ya. The thing that really has me stumped is why applying either the foot brake or hand brake causes the vibration to stop. From the perspective of the gear set, this should be no different than the additional drag of a hill, right?
 
Play at rear diff pinion flange:



GoPro mounted below when driving:

 
I'll just add based upon my own experience with several different diff shops/guys: The dufus in Sacramento that came highly recommended did the original install for the 4.88's on mine back in '06. They were a vibe, grinding & noise problem (with subsequent trips back to Sacto leaving the truck, etc., only to hear him say "everything's normal") until the rear damn near blew up 10-miles from ABQ apart of a big gathering of LC friends and subsequent off-road tour some 3-years later; 3-years of hell dealing with that asshat.

The effing guy was clueless. Once I had another diff guy tear down & set it up properly in ABQ (got to see first hand the pure irresponsibility and incompetence from the asshat that originally did all the work in Sacramento ...) it's been fine.

A couple years ago I pulled the front 3rd and had a competent diff speciality guy in Salinas rework the front diff ... and finally got past the Sacramento guy's "work". Wish I had the money back from that asshat ... hoping there is a karma god.

I don't know anything about your diff guy except to say there are more diff guys practicing their craft than experts in their field. Don't discount the fact you may need to seek a different guy. If your rig ran smooth until it didn't and without any changes whatsoever (upper/lower control arms for instance, etc.) then it has to be something driveline related. But you already know that. Methinks you need to find a more experienced shop to do the diagnosis work.
 
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