My car has the classic side to side shaking on acceleration, a shaking that I and everyone else immediately diagnosed as bad CV axles. I had the CV axles replaced at a local mechanic, but the vibration is clearly still there. I took it back to the mechanic and they said that they balanced the axles (which was a lie, because they clearly never took them off a second time to do so, nor would that be something that needed to be done) and then told me that the vibration may be a symptom of cheap tires. So they weren't helpful.
Since then, another vibration had arose which was clearly warped rotors. I replaced the rotors and that vibration is gone. Now that brakes are smooth as butter, but the side to side shaking that everyone diagnoses as CV axles is still there. The car is 2wd with 200k miles. There is only one carrier bearing, it is on the passenger side and it is part of the axle when you buy it, so it was replaced too. The upper motor mount/torque shaft had failed and was recently replaced too.
The only other idea I have is maybe poor alignment, but I would expect that to give other symptoms than just vibration specifically under acceleration. The car tracks perfectly, and there is no vibration while cruising or while braking. What do you guys think? I'm out of ideas.

 

Shaking on acceleration? How 'bout the engine mount/trans mounts? Also I'd look at the Lower A-arm bushings as well....

 

Hilarious!
I would like to see how they did that.

Did you have a chance to inspect their work and make sure they were actually replaced with new or did they just reboot the old ones and give it a shot of black paint. just wondering.

 

Haha I thought the same thing, but they clearly are new. Car's not mine actually, it's my fiancee's. She's was just finishing college when this started and her dad had the title to the car, he insisted on taking it to the mechanic the trusts without question, and since he was gonna pay for it, I said let it be. Now that the car is properly ours, so I can finally fix this infuriating shaking once and for all. It was when her dad told me that the mechanic had "Balanced the CV axles" that I realized what was really going on XD. Tomorrow in the daylight I'll take a look at the lower motor mounts and the a-arm bushings, they seem like a good next step. I'll post some pictures if I'm not sure of their health.

 

not sure if this is a possibility or not; but i had my 07 350 inspected by my shop not too long ago and they did say I had a partially torn lower control arm bushing that was 30 percent torn and at the time i was having a little shaking and i still am but im not totally worried about it. Thing is u might want them to check those bushings as well.

 

At 1:45 the failed control arm bushing can be seen to have excessive movement.
If the control arm busings are very bad it can be confirmed by having a helper putting the car in gear while someone watches for movement while keeping at a safe distance.
PS- I chose this video since the Toyota Sienna has a similar setup.

 

Really best to replace the whole A-arm which comes assembled w/ bushings/ball joint & I'd do both sides......Import direct offers them as well as Dorman.....Which one would I use, good question, they're w/ in $8.00 of one another.....btw How many miles are on your rx?

 

PS: $$ of work (11 normo-hrs) could be 10x $$ of parts )))))))

 

exactly!!! can u say OUCH!!!! i can!!! but then again if its gonna be apart to do one side; u might want to consider doing the other side.

 

Here's the lower control arms, one then the other. They look pretty suspect to me. I think I'm going to replace these and see if that fixes the problem.

 

Depending on your mileage may be original.
Appears to have some age and drying out going on.
The very small cracks are normal for high miles/age and don't go all the way thru so no real urgent big deal IMHO

It's when they are torn thru there is a problem and looks like yours may be but don't know if bad enough to cause your symptoms but don't look good either.

 

i agree those lca's dont totally look ok; they could be the originals which means depending on the mileage on your rx; it could be time to bite the bullet so to speak and pay up to get them replaced.

 

+1

The next is my lower arm. I didn't have any vibration or knocking sounds. The only problem I had was bad alignment (ball joint was also bad).

 

Those are shot!!! lolol

 

uh yea! id say they are shot as well! to say the least!!!