Vibrating Noise

[65sixbanger]

Ok when I am driving any speed over about 40, the floorboard vibrates for about two seconds then goes away. This happens about every 500 feet and it doesnt matter what gear I am in, or even if I am just coasting. Does anybody have any clue what this could be???

 

[OB_WAN]

How long has it been doing this? Did you do any work on the vehicle just prior to it starting to happen? Can you do anything to make it stop(accellerating, braking)? does it happen in a specific gear?

from my limited experience with these rigs, vibration is typically something in the drivetrain. tire balance, alignment, brake rotors/pads, hubs/wheel bearings, kingpins. ujoints, pillow block, gears. transfer case, transmission. don't know if I'm missing anything.

typically I get vibration in the steering wheel ~40+mph if it's balance related(in a front wheel). but that was on lighter vehicles. Not something with a 1200lb engine sitting on there.

I'll be curious about this as well. A buddy of mine commented on vibration in the passenger floorboard and I think we were going +40mph at the time. I couldn't feel it but may just be used to it.

 

[RWF350]

I'd start looking at things like u-joints, drivehaft, axles, bearings, even tires. It sounds like it will be something in constant ratio to ground speed, so it should be after the transmission. I had a ring gear chip a tooth one time (20 years ago), started soft like your describing then after a few days of driving it was pounding. But I'm pretty sure the occurance was a lot shorter than 500ft. Does it change with pavement type (concrete, asphalt, etc). If so I would look at tires or suspension first.

 

[Logroller]

look on the rear u joint at the pinion and make sure the ears on it arent worn out letting the u joint slap around

 

[65sixbanger]

I havent had a chance to look at it yet, its been raining and everything is wet. I put some 3/4" spacers on the front axle about a month ago and the noise disappeared. But the blocks made the tires point out and I dont have time right now to adjust the ball joints so now withj the nlocks out, the noise is back. Its just wierd how it does it every so often... Thanks
-Lance