rumble strip sound

I'm a new member to this site, but have searched around here before. Within the past 6 months, I've notice a "rumble strip" sound on the driver's side of my 04 Tacoma between 25-35 MPH. Its cyclical and does go away when 4wd is turned on. There is a new CV axle on the driver's side so I doubt that could be it. It hasnt gotten any worse yet, just wondering what it may be?

 

I had a rumble strip sound, vibration, more of a vibration though. Everything shook, like I had both passenger side tires on a rumblestrip. Took it to Toyota, they messed with it for a day and even took the drive shaft off and drive around in 4WD (FWD at that point). They didn't find anything wrong. They ended up checking the tranny fluid and topped it off. Ever since, I've had no problems. My issue was reproducible around 37mph-41mph.

 

does it vibrate the steering?

 

Its more vibration on the floor. I read on another site that 2nd Gen. had issues with the front differential bearing, not sure if that could be it. I changed both my diff, transmission, and transfer case fluids. The front diff had a lot of gunk, but no metal pieces or anything.

 

Did you ever get this vibration resolved?