My Hail Mary - need help diagnosing this shimmy / vibration (1 Viewer)

[trudd]

No thats my bad. Forgot to answer that bit.

Yes, its from the rear axle being out of plane, because of a fixed panhard, in my case due to lifting etc.
In yours, most likely due to sag, blown globe, and a weak shock on the left side which is now probably compromised.
Because of.. drumroll. Design flaw lol

You would also do my patented rear spring mod bc that is just wrong off the factory floor.
I am somewhat of a pioneer here,

Ok, this is starting to sound familiar. Was it also you who suggested replacing the Left side springs to match the specs of the Right side?

So, your solution is:

• match the springs on the Left and Right side of vehicle
• install adjustable panhard to bring axle back into plane
• replace shocks as needed
• make me sign a contract, in either blood or AHC fluid, which says that the engineers goofed and the AHC system is inherently flawed

Some good food for thought. Appreciate you chiming in here.

Also, it seems like the disagreements of the past are well known and don't have to be played out again here.........right?

 

[TeCKis300]

Welcome back @AnyMal . How's the truck doing?

@TeCKis300 - curious your thoughts on panhard theory. Seems like shocks are still worth replacing first?

Are you lifted in any manner? Sensor lift?

I would agree that with a more aggressive lift, the rear axle can be displaced but for a stock vehicle or mildly lifted one, it's non-issue. The way you describe you symptoms does not lead me to think it's the panhard. The OEM system is finely designed and optimal for the stock setup and it's not until we screw with things, that it needs adjustments. Sometimes it's a stack up of things that creates issues, but I don't think that's your problem?

 

[AnyMal]

Welcome back @AnyMal . How's the truck doing?



Are you lifted in any manner? Sensor lift?

I would agree that with a more aggressive lift, the rear axle can be displaced but for a stock vehicle or mildly lifted one, it's non-issue. The way you describe you symptoms does not lead me to think it's the panhard. The OEM system is finely designed and optimal for the stock setup and it's not until we screw with things, that it needs adjustments. Sometimes it's a stack up of things that creates issues, but I don't think that's your problem?

Doing good other than the single digit MPGs here inner city!!!
OMG
I also waited out for the model 3 refresh but now model s is cheap? It never ends in the EV world.

Truck is trucking. Its not so babied, i put it through its first carwash! Thats growth right?

Got some stuff from the Dr., doing some battery terminals, going to put in the lower trailing arms, and my UCA got recalled so, im putting that all off again lol.

Apparently the ball joints can fall out? @tbisaacs have you received notice?

BTW @trudd teck tecknically right that in a healthy system you should be within tolerance despite AHC doing its thing. Its just that the tolerances arent very tolerant!

 

[tbisaacs]

Apparently the ball joints can fall out? @tbisaacs have you received notice?

I never committed, so ball joints in tact. Welcome back!

 

[nwfl4runner]

Well, for the sake of everyone here, you should just ignore Teck's response if he takes the bait I'm just as likely to take both y'all's advice as I am to ignore it and blow that money on college for the kids.

According to an indie shop, a Cruiser specialist, and Lexus dealership: my shocks aren't weeping, but I imagine something took the additional force created by the busted rear left accumulator globe that I replaced.

I'm mostly empty in the rear. Usually have 3 kids in the middle row, sometimes their friends hop in the 3rd row. Occasionally tow a small 2,300lb camper and a week of food/ice/drinks.

I still don't have a fundamental understanding of what the panhard solved for you, but that's probably on me. I'll spend more time in your thread and doing some research. I still have a lot to learn about what each of these components controls independently vs. how they work together to determine drive quality.

If you aren’t lifted you won’t need a panhard correction. Take pictures of your shocks and post here and we’ll be able to tell. Can you be a bit more descriptive as to what you’re experiencing? Do the AHC settings materially change the road feeling? How’s your rear sway bar looking?

Edit - just think we should be baselining all the little stuff before considering going crazy.

 

[AnyMal]

Was it also you who suggested replacing the Left side springs to match the specs of the Right side?

BTW that wasn’t from my rear end, it was from a 200 series development product manager.
But also its the right thing to do on an LX.

 

[PDoyle]

I think checking the sensors would be your best thing to do before buying shocks.
The panhard would be way less of a PIA to install. Got this from the internet-

What does adjusting a panhard bar do?

Adjusting the right side track bar end upward moves the rear axle to the right, and therefore both rear tires. Adjusting it downward moves the rear axle to the left, and therefore both rear tires. Raising the track bar makes the car looser (oversteer) and lowering the track bar makes the car tighter (understeer).

 

[trudd]

How are your rear lower control and lateral rod bushings?

@PDoyle did a quick visual of the rear LCAs this morning. This was in H mode.

I also peeped the AHC sensors. The front sensors were right in the middle of the bracket and seemed untouched. Check out the rears, though. Is this standard, or does it look like someone adjusted just the passenger side?

 

[PDoyle]

No one, or very few have complained about the ride in the LX 570 when new.
But these vehicles are approaching 10 years old. Those rubber bushings are cracked and probably warn.
The shocks/struts are considered "vessels" right? If they don't leak and the AHC globes and fluid have been changed, then
if what you feel is coming from the rear your next focus would be those bushings. Not sure why the ride height brackets in the rear don't exactly match.