2008 TRD OR Rear Diff Whine Solution?

Firstly, yes I have searched and I can't find a solution, if you can point me to a thread I have missed that is much appreciated.

I have a 2008 TRD OR Prerunner with a rear diff whine, bought it at 116k and it is now at 145k with no real change in the severity of the sound. Other than now I notice it a lot more and would like to get it solved. I found a TSB (attached) but Toyota says there is nothing they can do about it now.

My Toyo mechanics looked at the TSB and said they couldn't figure out what would be making the whine. Their only suggestion was trying a different diff fluid. They changed out the rear diff fluid at 140k and didn't see any shavings etc.

Has anybody found a solution to this whine?

Thanks !

 

When is it whining?

On turns?
When pulling straight ahead?
When coasting in gear?

 

All the time. Worse between 50-70 mph. Basically exactly as it states in the TSB, which is why its frustrating that Toyota wont offer up a solution.

 

I think if it is as you say, you may be in for a new rear and you are beyond the warranty period unfortunately. They are sure it isn't tire or front wheel bearing noise?

Tire noise varies with speed.
Front wheel bearing noise generally is the same whether you are driving or coasting and changes when turning.
Rear wheel bearings will produce a vibration or growl that continues with the truck coasting and the trans in neutral.
Bad pinion bearings tend to make a continuous whirring or gritty sound starting at low speeds.
Ring and pinion noise is usually there whether driving, coasting or just barely on the gas maintaining speed.
Noise from differential action is worse in turns.

You could try the old school trick of adding Lucas Oil Stabilizer to the rear. It is suggested for noisy rears on the bottle with the suggested ratio. It will help quiet a rear end. I used it on a whiny Triumph Spitfire rear end and it helped to a degree.You may find you can live with the now diminished noise. If they found no metal in the drained oil it is apparently not chewing itself up at this point. Good luck with it.

 

Thank you, this is great info

 

I have used Lucas and found any "good" it does is short lived, I think that stuff is for used car salesman if you want a good oil you might try redline mt 90 it's a bit expensive but has performed very well for me but it's a bit expensive so you may want to inspect it or take it in to make sure your gears and bearings are in good condition