[abunaitwo]

1999 extra cab, 5 speed
It has a camper on the back.
Once in a while I get a buzzing noise.
Sounds like a lose panel.
Can't tell if it's from the front or rear.
I think the passenger side.
Probably not be able to help, but I just thought I'd try.

 

[shift_RUSH]

Does the pitch/tone of the buzz ever change? Such as w/ truck/engine speed?
Exhaust/heat shield issue is my first ventured guess.

 

[smj999smj]

Exhaust shield would be the first thing I would think of. Get a rubber or plastic mallet and do some banging in various areas under the vehicle, especially the exhaust.

 

[abunaitwo]

I think I found it.
Took some work and crawling under the truck.
There was a nut/bolt missing.
On the passenger rear of the bed. Second from the rear.
Really doesn't look like there was ever one there.
The bed looks like it has rubber washers between it and the frame.
I guess with age it settles down a little.
So far so good.

 

[abunaitwo]

I thought it was fixed.
Driving last night, it buzzed again.
Hard to tell where it's coming from.