duckJAI

I HAD this exact problem and it came from the rear. You would need a passanger to confirm this.

It seemed like it was coming from the diff, and once it was not 40mph, sound was gone. Slowed down to 40mph, sound came back.

It's very distinct and annoying.

I think it's the diff if it's coming from anywhere in the rear.

Have someone sit in the back seats and go up to the front passanger side after and see where it's louder.

kphu

iTrader: (8)

Actually, I wouldn't be surprised if its the diff because when I shift from Reverse to D sometimes I get a little bit of a clunk or its feels like a small jolt as oppose to a smooth transition. Is the diff covered by warranty i.e. if I take it to the dealer and ask them about the diff would they charge me for it?

duckJAI

I'm pretty sure your drivetrain warranty is over if your vehicle is older than a 2005.

They probably would charge you for it to check it out.

GS4_Fiend

iTrader: (22)

Try turning off the ASL in the audio see if it helps.

kphu

iTrader: (8)

Bummer....

I turn of the radio completely so I don't think it would make a difference, but I'll give it a shot.

It now occasionally happens.

duckJAI

Any update on this?

I got my TRD 1.5way diff inside now and I still get the humming/whistling. Probably not a diff issue since I had it even before with the open diff in the GS300

duckJAI

I may have found the problem.

I had my mechanic put the car on the hoist to see if we could find the problem, and we did notice the beginning of the driveshaft right after the tranny, where it bolts up it is somewhat loose and can be moved slightly left to right.

That might be causing the problem, not sure if its the same for everyone else though.