ebkw81

I have been trying to track down a vibration that occurs whenever the gas pedal is pressed for the last few months. It is most noticeable on the highway around 70 mph and it is felt in the floor board, seat bottom, and steering wheel. The dealer has been unable to find the problem after 6 visits.

2007 TL Base
Auto
No mods

Here is what has been done so far:
1. Replaced side engine mount
2. Replaced front engine mount
3. Changed tires 3 times
4. Road force balanced tires too many times to count
5. Replaced both axles with OEM axles.

Dealer keeps telling me it is my tires. I disagree. After changing them three times, I find it hard to believe that 12 tires would be defective. Wheels are not bent.

Based on the threads in this forum, I suggested to the dealer that it may be the half shaft bearing. The dealer told me that it would be making noise all the time if the bearing was bad. At my wits end, I did some investigation myself. Here is what I have found:

1. There is up/down movement in passenger side axle where it connects to the half shaft. The movement is very little (1 mm or so), but there is movement.) The inner CV joint has more up/down movement and (3 mm or so) and makes a clicking noise when moved up/down. There is no rotational play. The driver side axle and CV joint has no up/down or rotational play.

2. After removing the tires, I "drove" the car while on jack stands. Once I get into 4th and 5th gear, I start to feel the vibration in floor/steering/seat. Once the speedometer reads 70 mph, I start to hear grinding/scraping noise. It sounds both like a vibration noise and metal-on-metal noise. With the car running at "70 mph," I cannot see any movement in the half shaft.

Since I eliminated the possibility of tires/wheels causing this vibration, I am coming to the conclusion that my issue stems from the half shaft and/or bearing.

Does this sound like I am on the right track in my diagnosis? What perplexes me is that the noise is louder on the drivers side. I would have thought it would be louder on the passenger side since the bearing is on that side of the car.

I do not have much faith in the dealer diagnosing the problem, but unfortunately, it is the only one within reasonable distance to me. I am still under CPO warranty (drivetrain)and 3rd party warranty (everything else).

Experience, suggestions, and comments are much appreciated in helping me get this issue fixed before warranty expires in February.

4drviper

IMO most people at dealership including service advisors know about cars as much as a liberal arts grad lol

I usually see people with vibration problem with too much lowering so I came to say "stop destroying the car" but I saw you're stock so i went out, lifted my car, shaked both my half shafts.

There is no play (or i'm just too weak)

Wish I could help more.

PS : how about putting the car on a ramp or curb so you can try wiggling the half shafts while it's at riding height??