I am getting a growling noise from the rear end, similair to the sound as if you had a flat tire. As I speed up it gets louder not quite sure of the problem I was thinking maybe wheel bearing??

 

You'll need to check it. Wheel bearing is a good start. Jack up the rear put your hands on 12 I clock and 6 I clock positions and see if you can move it up and Down

 

might be an exhaust leak?

 

Other things that will help you narrow it down are 1) is it still there or worse when you have your foot on the gas accelerating? if so, it could be a u-joint or pinion bearing or worst-case your differential gears. 2) if it's the same whether you're coasting or accelerating (regardless of whether torque is being applied to the driveline) wheel bearings would sound more likely. 3)may sound stupid, and you probably already looked, but is there anything coming in contact with your tires/wheels like a branch or something stuck up under there?

Like Bloddy said, get it up on some stands and check the wheels, driveshaft, etc. for abnormal play. If you disconnect the driveshaft from the pinion you will be able to check the u-joints more thoroughly; and it will let you spin the wheels to see if you can feel any grinding or find any looseness isolated to the rear wheels or axle-area. That's where I'd start.

I had a ford ranger that the rear diff. gears went bad on, and it started out as a growling/whirring noise that was worse under strain. As it got worse over a few months, I could feel resistance kinda like the rear brakes were dragging. On the way to get it replaced I didn't need brakes at stop lights, just pushed in the clutch and it ground to a stop right quick! Mechanic said I had about 3 miles left before it exploded. Couldn't turn the wheels by hand when it was up on a lift! Don't mean to scare you or anything, but if you leave it, it will likely cause more damage and cost more to fix (or leave you stranded somewhere) - whatever the problem is. Good luck!

 

Its a constant sound and yes I already had it up on jackstands there is no abnormal play and the U-joints arnt sloppy at all and i had the differental cover off and drained the oil just some very fine metal specs which is normal no shavings to be seen and the gears looked fine so the only thing i can think of would be the bearings

 

and no its not an exhaust leak it no where close to the same sound and it only makes noise when the its moving

 

Anything like a rumble strip?

 

no not nearly as loud as a rumble strip

 

Just keep in mind. I was advised to grease spline and manually check back universal. I could not budge it by hand but once I took it down I found it was binding. Changed universal joint,greased spline,noise was gone. Hasn't come back.easy fix, just saying.