Hi everyone,

When I'm driving my 1995 SC300 on the highway, I begin hearing a banging noise around 60 MPH. The car begins vibrating and the noise becomes louder for a few minutes before it stops (all while driving 60+ MPH). If I happen to get off of the highway and slow down, I still hear the noise. I rarely experience this issue if I do not go above 60 MPH. As it does not change with acceleration, it does not appear to be an engine related issue.

Does anyone have any ideas about what this could be or what I can check?

Thanks very much in advance.

 

Where does it sound/feel like the banging is coming from?
Behind you or infront of you? Do you feel it in the seat more, or at your feet more? Is there a vibration in the steering wheel as well or no? Does the noise seem to go in time with the rotation of the tires, or with the RPM, or is it unrelated to both?

 

I've been feeling the same vibrations for six plus years. I thought changing the wheels was the issue...nope. Then I thought it was the shocks and springs...nope. Then I changed both upper and lower control arms....nope. The only thing I haven't changed is the bearing and rack/tie rods. I'll tackle both of those and provide feedback. If that doesn't fix it, then I would have changed the entire front end suspension which would lead me to the drive shaft/ rear of the car. However, I definitely feel the vibration near the front.

 

I had a similar vibration up front that was evident at highway speeds. It was also accompanied with a sometimes violent shudder in the steering wheel.
It went away when I got a brand new steering rack and whiteline rack bushings, so it's definitely worth a shot tabaka.

 

There's a number of threads that detail changing motor and especially the transmission mount eliminates a LOT of vibrations. If you've never changed these on your SC then its due.
I can personally attest that simply changing out the transmission mount eliminated any and every vibration that my SC had

 

Are you having an instability when driving? I have a similar vibration, but I'm also getting lateral instability too. Think about how it feels when you get some bump-steer, but I'm not going over a bump. Also, snow driving is pretty much impossible above 35-40mph and driving in the rain at highway speeds is a white knuckle experience do to this. Sorry for the hijack....

 

Wow, thanks for all of the replies!

eknine9, it sounds/feels like the banging is coming from the back of the car. I definitely feel it in the seat more, rather than my feet. I feel a slight vibration in the steering wheel but it's more from the car itself vibrating rather than the vibration coming from the steering wheel.

The noise definitely isn't related to RPM. It may be related to the tire rotation but it doesn't really seem like it.

canman44, I do not have any instability while driving and I NEVER drive my SC in the snow (I would never take the risk!).

scENFORCER, everything is original on the car so I'll look into this.

Thanks again everyone!