Shudder

I think I’m technically gen Z

 

That's between 15-30 years old if I remember correctly, I'm getting old and can't remember shit.

 

I believe that’s called “quenching”.

 

Wow what a thread, anyway…

Hit the exit ramps 4 times today and braked early to try and make the issue reappear. Couldn’t get it to fuck up, brakes smooth as ever and no shake. No wheel shimmy on the 60 road this morning either.
Crawling under tomorrow to inspect. Gotta get the creeper out for an O2 sensor anyhow. (P0136)

 

I couldn’t find anything wrong with it. All bushings looked good, Tie rods/ends were tight and looked good and straight. Brake pads are like new. Picked the front wheels up under suspension load and spun them, brakes felt even all the way around. Then I shook the wheels, no play.
Guess I’ll just wait until it does this again, and see if I can pay more attention to how it feels; or where it comes from/seems to come from.

Also, the 02 sensor nuts weren’t even nuts anymore, just round rust collars. Had to vice grip them off and make some new ones out of 2 stainless 1/4-20 nuts that I drilled out and retapped to M8-1.25. (RIP to those 2 17/64 drill bits)
Quicker than driving to Lowe’s!

 

You've checked everything else, check the air pressure in the tires? Have you noticed if it's the same sections of road where you feel it?

 

Maybe the lick the finger, touch the hot rotor test next when it happens?

Maybe the caliper was dragging a little and you unstuck it? Who knows.

 

They were all at 45-46 when I jacked it up, which is what I keep them at.
And no, the shimmy when not braking just seems to happen at random and then go away. Like a fart in the wind.

 

Holy cow that’s high psi; maybe try dropping it down to 35-40; you could just be feeling road irregularities with how much you’re gonna feel through the tires

 

Maybe a stupid question here, but ... does it always seem to happen on a specific stretch of road?

I only ask because there's this one section of I-85, just south of the ATL airport, that makes the wheels in our 2020 Highlander shimmy the wheel.

I've also noticed some wheel hop in the truck, but it's totally intermittent. Occasional steering wheel shimmy associated. But it's really mild. I tend to ride with my wrist at 12 o'clock, hand hanging off with my fingertips over the dash. If my fingertips are moving, I know I've got some shimmy.

 

They’re 80lb LT E load tires, 35 kinda makes them look flat. I remember doing some mathematical equation to find out what pressure to run when I got them. I thought 46 was high but they’ve been wearing even.

 

No, it happens on all different types of roads, just not all the time.
Like you said, I can feel it when my hand is on, but can only see it when my hands are off.

 

Curious, any sounds? Have you checked your rack bushings lately to make sure one isn't blown out? I'm just trying to think of anything that would lend to the variability you're describing.

 

Again, go get your tires rebalanced just to check all the boxes

 

Pretty much same thing I’m running; I stick between 35-40

 

Another thing that came to mind: Have you checked for loose or clearly missing wheel weights?

I've found a couple since the last time I had my tires balanced. The balance jockey at my local Discount apparently didn't wipe to remove residue off the inner wheel before sticking on the weights, or did something else, because I found one flopping around, and a small chunk of foam where it appeared one may've been living.

I can imagine, if you have a strip of 6-8 weights in a row, and you only lose one, the shimmy would maybe be intermittent or barely noticeable.

 

Yeah the wheel has to be barely off balance to do the shimmy y’all are talking about; just a little or a poor balance will do it

 

Yes, the rack bushings are tight. Looked at them yesterday.

I will get up under and look for any missing sticky weights, sounds like a promising idea.

 

Dude, just knuckle down and replace the OEM rubber rack bushings with polyurethane bushings.

 

The whole rack was replaced in 2019 and it has poly bushings

 

Finally got around to checking this All the weights are on tight, and I don’t see any bare stick foam that would suggest missing ones.

 

If weights appear to all be there, its a bit of work but you could try removing the tires and rolling them individually across your driveway or any other perfectly flat surface and see if they wobble excessively indicating lopsided/out of round tires (balancing wont correct this, its usually a result of bad alignment/aftermarket suspesnion/lift kits). When I first got my truck, it had 4 different tires and 3 of 4 of them all fell over after one or two rotations instead of rolling straight. Got 4 new tires mounted and balanced and it felt like new.

Driveshaft center support bearing is also something to check. If you replace it, get a Spicer/Dana brand one. (Unless you've got the coin to buy OEM.)

 

Just go get the balance checked on the tires

 

You know you have a quality tech balancing your tires when it’s a different reading every time he mounts & remounts the tire on the balancer. Then there’s like way too much weight on each rim as a result. haha

I’ve been through that several times before.

 

On a (maybe?) unrelated note, my 11-month-old Rough Country coilover struts bottom bushings are basically worn out. They warrantied it no questions asked and I’ll install next weekend when they get here.

New ones also come with 3 year warranty.
Maybe I’ll get new struts every year for free? =)

 

They give you a whole new strut? Last time I had a shot bushing on my Bilstein shock, I just replaced the bushing, coilover intact.

 

Man on the phone said “The bushings aren’t replaceable because they're galvanized in there”, and sent me BOTH struts for free. Even free shipping. What’s not free is the half a Saturday it takes to put them in.

The Struts are in good shape, but the bottom bolt is almost touching metal.

New 2.5” loaded coilovers are 369.95 on RC website.

 

Threw the struts on today, did some looking around underneath after. Carrier bearing is out bad. I can push up on the DS and it has an inch of play at least. Could be the shudder cause. Anything I should know before I order one and slap it on?

 

If you really wanted to rule stuff out and do preventative maintenance, you could order new U joints for the driveshaft as well and just take it to a shop and have them install everything and balance the driveshaft/check it for balance.

If your truck has over 200k, it would almost be a waste to not replace the U joints while replacing the center support/carrier bearing.

If you decide to do it yourself, skip to 17:33 of this ChrisFix video. When replacing U-Joints, a lot of people don't check them for freedom of movement after pressing them back in, he taps them with a hammer to "settle" everything into place. Many people aren't aware you're supposed to do that. They can be prematurely worn out if they are bound up.

https://www.youtube.com/watch?v=5gOeBE-ylQw&t=1059s

Again, remember to stick with Spicer/Dana branded parts for the driveshaft. The tiny savings by going with moog isn't worth running into trouble by buying cheaper parts.

 

Driveshaft won’t cause steering wheel shudder