I agree with David. Mostly because the vibration you are feeling is at a specific speed range. That to me indicates something reaching a harmonic. Usually that is something to do with a wheel or tire!

 

I've swapped tires and hubs with no change in the vibration. With the toe movement I'm fairly certain it's not an issue with the tires or rims. I've been researching and I'm definitely leaning towards track bar bushings. I'm having hell finding as place that sells them though.

 

The rear bushings on the sway bar are a goofy shape.
Take a look at this thread about making poly bushings (it's for an Impala, but the parts are the same as the Monte):
poly bushings - 2000-2005 Wheels, Tires, Brakes, and Suspension - NAIOA

I wonder if the strut itself is causing this.... I only say this because you are running out of options on this one. I assume the lateral and trailing arms all look good, no bends that might knock off the alignment??

 

other than being dirty everything looks flawless. You think the entire strut is the issue or maybe just the top plate?

 

A bad top strut mount and out of balance tire and or a "Bad" tire will cause that same kind of vibration...

How old (yrs) are the tires and how many miles on them?

 

Well I found in issue an communication, the part i think is the issue is called the lateral arm in my hayes manual, the rear control arm in an ACDelco diagram, and the guy I always call for advice knows it as a track bar.

I've attached a photo Maniac posted in another thread of the part.

The bars themselves look perfectly straight, and the bushings look old but solid.

Now looking at rockauto I've found bushings with all 3 of those names, and when pulling the rear one off and examining it I'm not sure I'd be able to replace just the bushing anyway. So now my question is, is this most likely the cause of my issue, and would i be able to swap both the front and rear lateral arm from the driver to passenger side to make sure this is the issue before i start ordering parts?

Right now I'm dealing with a lot of suspension issue and have decided to go ahead and replace all faulty parts in pairs, meaning i would end up buying 2 fronts and 2 rears at 60-70 a pop, along with 200 worth of bushings in the front, mainly because tearing apart the front end is a pita and I dont want to need to do so again for a few years. The rear on the other hand is fairly easy for me to tear down so if i can get away with only replacing the ones on the problem side I'd be happy.

Lots of questions, hopefully yall got answers lol.

 

Interesting find on the bushings. I suppose that could cause an issue. I hope this is finally a means to an end.

The front and rear laterals are the same from left and right. SO, in theory, yet you can swap the left and right sides. BUT, keep in mind, they are adjustable, so swapping sides may mean that that need re-adjusted for the rear end alignment.

If you are physically seeing the bushings are bad on them, I don't think I'd worry about swapping them.

FYI - I looked at RockAuto's site. If I follow them correct, look under lateral link. If I recall, the Monte has one that is adjustable and the other is not. Looking at Rock's catalog, the "rear rear" lats are adjustable and the "rear front" lats are not. None of the lats are over $35 a piece.
I'm not sure what bar is listed under "track bar".
Since you're in Texas, I'm making a wild assumption you Monte is not rusting underneath, so the lat bars themselves are fine. If you look with companies like Energy Suspension, you MIGHT be able to buy poly bushings and replace your bad bushings. Heck, maybe ZZP or someone has something already available.

 

Alright well when i had googled 03 monte track bar the first one was around $70.

Most likely gonna order all the parts on thursday after i get paid, but definitely gonna play around with the rear end to make sure the laterals are the issue. If they are I'm gonna go ahead and do both the front and rear on the drivers side.

Now to go off topic a bit, I'm gonna be purchasing all of this.

2 sets of control arm bushings MOOG
2 ball joints MOOG
2 outer tie rod ends MOOG
2 front poly stabilizer bar links MOOG
2 rear stabilizer bar links MOOG
2 sets of trailing arm bushings from MOOG (why the hell not?)
plus a set of lateral links for the drivers side

With shipping I'm looking at 333.16, and I'm willing to spend up to $400 if theres anything else I should do while I've got all this going on.

Oh and I will be getting an alignment right after i slap it back together and new tires next payday.

 

First, if you are replacing the bushings and ball joints on the control arms, I might recommend pricing a full replacement control arm. The bushings are pressed in and can be a PAIN to get the new ones in. Plus the ball joints have to be drilled out to remove them. Looks like via Rock it's $70 for a MOOG lower control arm. So you're not saving a lot rebuilding the factory arm.

If you are going for full bushing replacement, there are two bushings in the front and two in the rear that hold the sway bar to a cradle.

Outside of that, I think you covered it all.... But if you are doing one set of lats, you might want to replace both (especially if you are refreshing all these bushings).

 

Well I just swapped the lats around and now theres zero toe movement from either tire. I guess that means I confirmed the issue? I expected the wiggle to go from the driver side to the pass when i moved the lateral bars but they're both solid now, so I'll go ahead and replace all 4 of em.

Thanks for the help you guys, especially Maniac!

If yall got any other advice to toss in let me know, I'm ordering everything tomorrow once I cash my check.