It is constant affected only by speed. On throttle, off throttle, cruise - makes no difference.

I think I'm going to go ahead and change out both rear wheel bearings and see how that goes, even if only one is bad its probably worth doing both.

 

did you end up fix the problem yet? I have same sound right now in car.

 

I've put two new rear wheel bearings in and no change.

I've researched some more and worn pinion bearings in the diff make the same sound. In the process of removing it I found there is no play in the driveshaft but there was play in each of the axles at the diff. I also found some metal fragments (like tiny metal splinters) around the axle seals.

I'm yet to actually inspect inside the diff.

 

I see. I hope nothing serious with your car.

 

Almost sounds more like a creaking to me? My 05 evo was bought and has less than 30k miles on it and the front wheel bearing was shot. Possibly the rear. Oh well I ordered ceramic bearings hope it fixes the issue.

 

Right, an update.

So I removed the diff, when I rotated the pinion by hand it was very lumpy/chunky/bumpy, however you wanna describe it, it was not smooth at all. I sent it STM NZ and had it inspected.

The response was that the pinion bearing collapsed, they fixed it up and sent it back with the old/damaged parts (with a free chocolate bar, score!). One of the bearings was completely ****ed, see pics. Royally ****ed in fact. Now that it is back, I can turn the pinion by hand and it rotates smoothly.



Unfortunately it might takes a while to get it back in and running as I've got some more work to do before it hits the road again, but I will definitely post some feedback when I do.

 

Glad to hear you at least got to the bottom of the cause of your issue....I got lucky I changed my complete Hub assembly in the passenger rear & the noise completely went away now.

 

Right!

Final update: Diff is back in car and has been running great for a a couple months or so. I am planning on starting a thread that will look into what caused the failure(and maybe other evos).