When I'm driving around 50 to 55 on highway my car starts shaking or knocking. Will this be the transmission issue, and is it fixable? The car has approximately 140,000 miles. So I'm assuming the transmission.

Thanks

 

Personally the first thing I'd check is tires. I had minor shaking that rebalancing/rotation only fixed for a short period of time. Ended up getting new tires and it solved the problem.

 

Maybe you have Elvis under your hood...

But seriously, shaking at a particular MPH is usually associated with tires and either misaligned or out of balance, while knocking could be from using regular gas perhaps?

Unless the RPM is also fluctuating and going nutty during this MPH, I'd almost say it's NOT a transmission problem. JMHO.

 

As long as the RPM's aren't surging and changing, it's safe to say that it's not a transmission problem. I do agree with the others first thing to do is check the tires out. Does it always knock when the car starts shaking? Check the lug nuts to make sure they are tight...I've come across cars that I could take the lug nut off by hand.

 

When its on DRIVE not moving complete stop the RPM tends to move up and down. Which is an issue. I will go get the tire checked out this weekend. I had the same problem during the summer, and I got it fixed so I guess it is the same issue dkpnkc.

Thanks all for your help, more reply will be great!!

Thanks

 

If the RPM's move when idling in drive. You should clean out the MAF, throttle body and IACV. All of these can be done by the DIY's on this site. You probably don't need to clean all of these, but cleaning all of them won't hurt and it'll only benefit with some better mpg's and performance.

 

I did this last night & it's well worth the 30-45 minutes. Easy to do w/ the great instructions on this site - and coming from me means it's really easy

 

I have done all the maintenance listed on this forum https://www.clublexus.com/forums/rx-...-write-up.html
here is the link, and change spark plug timing belt and etc, which were mostly recommended one.

But I will check the IACV and just clean it up again.

Is there another recommendation that I should do?


thanks again