I have a 2007 Lexus RX350 (girlfriend's car) 2WD with about 155K. About a month ago, she had the tires rotated and balanced. Almost right after that, she was complaining about a vibration. I drove it, and didn't notice anything so I said not to worry. Then, 2 weeks later, I drove it on Easter, and it was pretty bad. It felt pretty similar to a misfire, which we've had happen 3 separate times on this car in the year we've had it. I replaced the coils and the problem was fixed. This vibration feels very similar to when it misfired, from about 35-50MPH under a load. Braking at first didn't seem to make it better or worse. I drove it and got up to about 90, then braked, and it started shaking even worse. So, I figured that meant I had a caliper/brake issue. Just in case, we took it back to the place she has them rotated at, and rotated back. They also checked the balancing and it was way off. I thought I'd get lucky and that would be it. So, moving forward. Maybe the caliper guide pins were sticking. One of the rotors looked like it was scored pretty bad in the front, so I ordered new brakes for the front, rotors and pads from Centric. Just changed them out yesterday and it seemed to have fixed the vibration issue. But my girlfriend texted me when she got to work this morning that the vibration is still there.

I'm basically at the end of my diagnositc capability. The only other ideas I have is it's an axle or transmission issue. The fluid is full, but pretty dirty. When we bought the car it was a nice rest color. It's now like a dark color red. We've put a little over 20K miles on it since we've had it though.

Drive side CV boot on the in ER side is torn. I saw a grease sling above the boot yesterday when I was doing the brakes. But it looks fairly new. I don't think they go bad immediately after the boot tears though, I could be wrong.

Wondering what route to go next. If I should have the transmission fluid flushed. Replace an axle. No check engine codes. I checked anyways and I'm not finding any codes of any kind.

I will say I'm disappointed in this car since we've bought it. I have had more problems with this car than any other car I've ever owned except for project vehicles. Could, wiper blade system/motor wiring, leaks, sunroof plastic cables broke, suspension issues, window issues. None of it has been hard, but I'm frequently having to fix it. My 03 Camry with almost 300K miles I paid 1700 for a year ago and I've changed the oil once, and that's all I've done to it. I just wished this car was as simple as that.

 

Vibrations from worn axles are sensitive to load/noload at the same speed. I.e., if driving at 60mph, and then accelerate, if vibration immediately gets worse, or reverse, getting off gas, then axles a likely suspect. 155K seems about average life of CV axles for my cars. Bad axles can be hard to diagnose just by tugging on them, but they should get progressively worse as miles add up, likely no sudden failure.

 

It does not really seem to vibrate much or at all unless you accelerate and only in the 35-50 MPH range. Since I have done the front brakes and greased up the caliper guide pins really well, I'm assuming it's not the brakes. The wheels were balanced right before. So my thought it I'm looking at an axle or transmission issue. It's 2WD jot AWD, so no rear end issues on it.

 

My money is still on the axles, but you can drive a long, long way before actually replacing them, wait until it gets really annoying.

 

When I drove it last, it felt like a misfire, so it's pretty bad. I'm planning on selling it as soon as I figure it out.

 

Anybody know what brand the OEM axles are I'd they aren't Toyota? I'm going to call Lexus tomorrow and see how much they want for each axle.

 

Is it possible to be transmission shudder ? Like you are on bumpy road ?

 

that was my original thought until the brakes started shaking when applied. Figured I was dragging a caliper. Did the front brakes, and it's still there. It seems to be intermittent. And only at a certain speed range. Accelerating faster in that range exaggerates the problem too. And then it smooths out and goes away after about 50-55MPH

 

Could still be the tires if the shop didn't know what they were doing or had a new tech.

 

That was another hypothesis if mine. She brought it to discount tire where her younger brother works but he didn't rotate/balance them, somebody else did. This problem came up a day or 2 later. We brought it to another discount and they said they are pretty confident whoever did it last lied about doing it because they needed to be rebalanced pretty bad. So they did it and it seemed fine for a day. Then, it came back again. After I did the brakes, it seemed to go away. Next day, it was there. My girlfriend said it was just as bad as before after I did the brakes, then I drove it yesterday, and it barely did it. It was just enough to notice it was there for me. She said it was a lot worse for her.

 

Odd. How are your tie rods and ball joints?

 

Ball joints look ok. No popping noises and the boots aren't torn. Tie rod boot looks slightly torn though.

 

I would "dig" in this direction. First, check the tires. If you don't want to buy a new one - find the owner of another Lexus RX (who doesn't have such problem), and ask to borrow the wheels for test drive.
How old are tires? It's possible that tire can be balanced on stand, but it becomes unbalanced when you drive (too old and/or has some inner damage).

 

Tires have about 50-60% life left on them. Balanced and rotated regularly. Probably every 4000 miles when I change the oil. They've been rotated and balanced twice now since finding this issue, and it isn't fixed. Tires are a little over a year old according to the date on the tires. They aren't directional tires either.

 

Unfortunately, all these can't confirm that tires are still ok.