2005 hyundai sonata shaking

I posted a couple weeks ago about my sonata beginning to shake at speeds above 60 mph. I took it to a local dealer, who could not find a prpblem, so I took it to the dealer and they said I need to replace the rack and pinion, gat my car aligned and balance and rotate my tires. I am concerned this is not the problem and the dealership is trying to get money out of me, especially since I had my tires balanced before seeing them.
This problem is intermittent and happens in the afternoon, not at morning or evening times. It takes about 15 mins to begin to shake and will stop if I get off the interstate and come to a full stop.

Don’t let the dealership touch it. They have no idea what’s wrong and will just throw expensive parts on it. You may have to live with it for a while until it gets worse so that someone can really find the problem.

One possibility is a bad front axle. These can wear out over time and cause a shaking/vibration at high speeds or under acceleration. Does the shaking get worse with acceleration?

Get a second opinion?

A couple of thoughts:

Getting the tires balanced does not mean that they were balanced correctly. The last time I got tires on my Acura I had to go back 4 times before they finally got the balance right. You might consider asking if the shop has a road-force balancer - it tends to return better results.

Let’s narrow down the cause of the problem: When it starts shaking, make sure you’re in clear traffic conditions and then put the car in neutral and take your foot off the gas. If the shaking stops, you know it’s not the rack, tires, or alignment. Unfortunately you also know that the problem is in the engine or transmission, which might be more expensive.

Also, describe the shake more - is it a vibration, a wiggle back and forth, bouncing up and down, or what? Does the steering wheel wag back and forth when it shakes?

just FYI, one time I had a really bad shaking problem on my car. The whole car shaked going over 50mph, felt like it was coming from the front. Had the front tires looked at and balanced. Still had the shakes. It was actually dirt caked on the back rims that was causing that.

The dealership is tying to rob you. The only conceivable way a rack can cause shaking on the highway is if the joint at one of the tie rod ends is bad, and those are replaceable. That’s considered a tie rod problem, not a steering rack problem.

I’d recommend getting the chassis checked by a reputable independent shop. They’ll check out the tie rod ends, struts, ball joints, bearings, and a few things that I’m forgetting.

Find one that also has the capability to do Road Force Balancing of the wheels. That’s a machine that balances the wheel & tire while placing a simulated road force on it, by pressing a spinning drum up against the tire’s tread while the wheel is being checked for balance. That’ll detect internal tire problems and/or damage that regular balancing machines will not. Not all shops have these machines.

Any decent shop will “read” your tread, too. How a tire wears can tell a lot about its dynamic movements, and, in addition, if it should have irregular wear patterns it might not be able to roll smooth no matter how well balanced it is.