I started hearing a humming noise coming from my rear axle when i let off the accelerator usually above 25mph. then finally I lost the connection to the rear axle, so i ran it in 4 high until i could take a look at it. I took the cap off the diff and noticed my ring gear had come completely off it appeared that only 4 of the 8 bolts that hold it in place had been put in. the 4 bolts broke off and reduced to almost metal shavings so i put new bolts and i can drive with the rear axle again but im still getting the humming noise when i let off the accelerator.(also it gets a very slight vibration while my foot is on the gas above 45 mph) so i was wondering if maybe when the ring gear broke free it may have thrown the pinion out of place or could it be something with the axle bearings or shims?
any ideas would be helpful

to much backlash it sounds like

To much backlash? I dont know a whole lot about axles just what ive learned from taking it apart to put the ring gear back in place.