Reducing Noise Inside a Car

It could be that the panels that make up the rear section don't have anti vibration mats stuck to them! Or it could be insufficient lubricant in the rear diff or even the actual tyres on the road making the noise! Check the lube and try to add sound deadening material to the rear floor pan!

This is only my guess, I don't have any professional advice for you but I have played with a few cars in my time with similar problems!

Good luck, and if you can't solve the problem, you could always drive slower and enjoy the scenery!

This may be overkill, but check out this thread.

That's the stuff! Anti-drum mats or in Mooses case anti-drum-and-base mats!

How aggressive is the tread on you tires?

Mud terrain tires can really howl at high speeds. But by the sounds of it - you have a small car and not a 4x4 - but just a thought.

The list of things that can make noise is long.

First, check for rear axle lube. If the car is rear wheel drive the lube is critical to the life of the rear gear system.

If the rear gear oil is full, next check the air pressure in the rear tires.

Next on the list would be to drive on left, and then right curves. If the noise is louder on right curves than left curves, it could very well be a LEFT rear wheel bearing. If the noise is louder on left curves, It could be the RIGHT wheel bearing.

Try lowering the rear window on the right side and driving next to a building. A car spaced six feet from a building will bounce a lot of noise off that wall and back to the driver. Next drive with the building on the left, and see if the noise changes.

If you still think it is an abnormal sound, switch rear tires from left to right and drive again.I have seen some tires that were just fine in wear, tread depth, and all other things to look for, but when the rear window on the car was lowered there was a harmonic that would set up at about 35 mph, that sounded like a timpani drum at a low frequency. You would swear your ear drums were going to pop.

Good luck.

http://www.acoustiblok.com/uses.html#automotive_car_sound_proofing

Well said Andy. Bad wheel bearings can lead to sudden wheel lockup. Even without wheel lock up,heavy spindle damage can be caused be seized wheel bearings. I hope the OP will heed your advice.

Been there, done that, no fun. I was only traveling at walking speed (turning a sharp corner at a stop light) and had a front bearing lock up. The steering wheel snapped around one and 1/2 complete turns in around 1/10 sec. Had I been driving with both hands on the wheel, it would have snapped both arms instead of just 1. Thank goodness, I had a beer in my other hand...

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I'll need the following:

Length, height,width of car

Drive train composition- describe shaft-bearing-wheel set up

Wheel base height and width.

Empty weight

Loaded weight

"Humming sound" causing the "humming noise" is caused by a "threshold resonance" caused by Envelope and SPL compounded waves.

My offer to do this at no charge is real. The only thing I ask in return is for your future feedback and reference related to my assistance. References to be requested in writting prior to me giving you as reference. If this is Ok, then ; your answers will help me help you. Also, if you have any pics of the cart inside and out that will also help.