vibrating under the driver side floor pan?

[srkpaco]

I have an 2004 LC stock except for torsion bar crank and no running boards. It drives great and no leaks anywhere but at 75 mph's at around 2600 rpm there is a vibration under my drivers side floor board (kind of a hum). Could be the front drivers side wheel bearing or the front drive shaft? Is there any thing I should look at before I go on a wild goose chase?

Thanks in advance.

 

[marshotel]

Check to see if there is anything stuck in the tread of the tire.

Maybe switch the RF and LF wheels and see if the hum disappears or changes location. Then you would know if the problem is related to the tire or wheel balancing.

I used to have a vibration at about 75 mph, rotated and balanced the tires and the vibration went away. (your mileage may vary).

 

[srkpaco]

It is not my tires. It is either the front wheel bearing or something to do with the front wheel drive system? Is there anything on the front wheel drive system that needs to be greased or replaced on a regular service?

 

[Trunk Monkey]

Yes, plenty. Hubs, CV's, front diff lube, drive shaft joints.

 

[srkpaco]

Thanks Trunk Monkey, I don't think it is the hub or cv's. What service is recommended for the front diff. lube and drive sharft joints? I am a new owner and since I don't have a soild front axle i didn't think there was a front diff? Is there a front drive shaft?

 

[Trunk Monkey]

Power has to get the front wheels somehow - front drive shaft, front diff and then CV's. You change diff fluid just like a SFA and lube the DS u-joints.

 

[KlausVanWinkle]

Have you already had to do the metal clamp around the cats to get their heat shields to stop rattling?

Is the vibration related to a specific RPM or just the specific speed. Find out what RPM you're at when going 75mph and do the same rpm at another speed to see if it makes the same noise.

If it's a wheel bearing, it'll increase with speed, sound like a helicopter and change when going around curves like a highway entrance ramp.