When on the highway at anywhere from 40 mph and up occasionally I will get a 2 second vibration noise that sounds like I drove over a road strip. Sounds like a hammer drill. Then drive for 30 - 50 minutes and it happens again. Dealer does not know what it is. Any Ideas?

 

I would suspect the U joints or hub bearings. The U joints particularly if you are in a turn when the vibration occurs.


You might want to check the exhaust system is not contacting the body and more remotely the parking brake is not hanging up.

 

Thanks for the suggestions. Someone new will be looking at the car soon and I will tell them. I'm just hoping it is not the differential. The vibration happens or is most noticeable on the highway going straight. If I drive 60 miles I might hear it twice. It's very noticeable.

When I back and then turn out of my driveway about 10% of the time I might hear something that sounds like a water bottle in the trunk / wheelwell. And even less often I hear something that sounds like a brake hanging up that goes away after I travel about 50 feet. One time 5 years ago I heard a bang by the differential just as I started moving forward but no problems. 3 years later I have intermitent 2 second fairly deep vibrations at the rear passenger wheel that I notice when I'm going +45 mph. I love my 04 xjr and don't want to trade it in. I hope this will not be too expensive.

 

+1 on Tarheal's suggestions.

Note that the X350 has Constant Velocity (CV) joints rather than traditional U-joints.

A few hair-brained ideas:

Could your Electronic Park Brake (EPB) actuator or passenger side caliper be seizing or binding?

The air suspension reservoir and valve block are in the floor of the trunk under the spare tire/wheel. Could the valve block have a valve that is binding and vibrating in an unusual way? This could be related to the "water bottle in the trunk" sound you're hearing. By the way, have you carefully looked under the floor and behind the trim of the trunk for anything loose and rolling around?

Could the CATS solenoid in the rear passenger side air spring/damper be binding or making noise as it vibrates while adjusting between Firm and Soft modes?

Could your Anti-Lock Brake system (ABS) or Dynamic Stability Control (DSC) be malfunctioning and improperly pulsing the rear passenger side brake caliper?

To help isolate unusal mechanical noises, you can chock the front wheels both fore and aft, raise the entire rear end and set it on jack stands, start the engine and put the transmission in Drive, then while laying alongside the car but not under it, carefully probe all the potential suspects with a mechanics stethoscope ($10-$20 at local auto parts stores). Touch the probe to a non-rotating area close to each rotating part, never to the rotating parts themselves.

Did the dealer scan the car's modules for stored Diagnostic Trouble Codes (DTCs)? Many malfunctions with the ABS, DSC, air suspension, etc. will trigger fault codes.

Please keep us informed!

Don

 

Thanks Don. I will look into those items and report back. No diagnostic codes from the dealer,...I know that much.