Do any of you have an educated guess as to which one it is? I found a tranny on c-list for $180 and a VLSD diff for $280...Id most likey just get the 1.6 diff since Im a poor bastard and can't shell out the $500+ people are asking for a 1.8.

I wouldn't know how to tell since they both sound so similar when they fail, but if it does it in every gear I would gamble and change the diff. Its easier to change than the transmission anyway.

Ticking time bomb.

Put fluid in it. I bet it's really low, and that's your problem.

I would still budget on putting a trans in it, though, lol.

Can't tell you how super excited I am to hear all these positive comments. Heres to tranny fluid fixing it

I'll throw this in...My 96 torsen made a sound like that, on the freeway it sounded like pads dragging on rusty brake rotors. It had horrible lash and a bad bearing. I ended up with another out of a junkyard thats almost perfect. It has a slight whine when on the gas at like 55-60 mph thats not there unless im on the gas. A whine is one thing, youll know cause its a humming sound-not too sketch until it turns into the break drag rust y rotor thing. It doesnt help that i have no interior in the rear half of my car either.
I'm pretty sure that yours is a differential issue because it does it in a few different gears only when accel. Could be bad pinion bearing but either way the 1.6 diff is sketch to begin with if your going to have any "fun" with your car and trust it to get you back home lol.
+1 for diff swap!

Same problem any help or any suggestions
 

I have a 2004 miata and its doing the same things its making a whining noise that sounds like its coming from the tranny it sounds like its coming from there but today i lifted the rear end had someone "drive" it and it clearly sounds like its coming from the diff. i had someone else look at it also they said its the diff also so I'm not sure if anybody had any solutions the fluid was changed today they suggested to drive around for a week and then see if it changes.

Does it do it in 4th gear?

It does it in Every gear especially once you get going it gets louder. The people that looked at it are sure it's the diff. And once i put my ear up against it I can hear it. But when I drive it sounds like it's coming from the tranny but again sound travels especially in this car

First time poster here, and resurrecting an old thread, but....wondering what your resolution was to this problem? Have just noticed this whine recently in my 91 as well.