Just was out on the weekend and started to hear a very slight wirlllllllll sound when slowing down using the engine as braking (no brakes), if I pushed the clutch in, the sound would stop. Do I need to be worried or just let it go until it gets worse?

 

Check fluid levels, otherwise you'll have to wait until it gets worse to see if you can better pinpoint what is making the noise.

 

T-case whine at all seriousness will whine at all times when the car is moving.

Most evo's have some normal drive train noise with accelerating/decelerating (especially if you have some poly bushings).

 

Not true. Mine started as a decel whine once..

 

In a way, yes. Decel is a big proponent to transfercase wine if your bearings are starting to go. Needless to say, if you wait to long to rebuild it, you could ruin the gears causing you to buy a whole new unit. Can you wait until you hear it all the time? Maybe, but why chance it.

To verify, I would change out the fluid to see if you see any sweet sparkles.

 

Mine was the gears making decel whine, not the bearing. Bearings usually don't start out as a faint noise. If they do, they get loud quickly.

 

I found that tcase whine is easy to hear, when you are in 5th or 4th, and press the throttle. It will usually go away when you remove your foot off the throttle. Also, it always sounds like it is coming from the back.

 

It can deviate by case to case.

What normally causes gears to grind? Bearing failure.
How can it be picked up early? Looking at the oil.

I would disagree with your assumption of a faint noise, as this is how all bearings start out and they do get louder over time. What that timeframe is, is also situationally dependent.

Im not trying to be rude one bit, I just want to point out that if a noise is starting...its always best to catch it sooner rather than later.

But to your point, everyone has see a different situation.

 

Since I've had issue with a well known drivetrain builder having issues with my tcase living more than 1k miles, twice, I can tell you that gears with bad setup can start out as faint noises and get louder. Bearings can too. But unless the tcase was underfilled, it's really hard for roller bearings to go bad.

 

I would agree.
Sorry to hear of your loss.

 

I'm reading you guys, I changed out all oils a year ago with OEM slightly overfilled the gearbox too, I might go for another run on the weekend and get under it to check the levels

 

1. Tcase is in the front of the car.
2. It should whine 100% of the time

3. The sound your referring to is diff noise and extremely typical of cars especially if you have polyurethane bushings. Most evos whine around 3kish @ 65-80mph,

 

My transfer makes all kinds of racket on decel and its been doing that for thirteen years.

 

sounds like the only way to know is to look at the oil?...

 

Back before I even thought of buying an Evo I had this rally car computer game. In the game my favorite car was the Evo. It made quite a racket in the game and I learned what that racket was when I bought an Evo (they evidently had used an actual sound track from the car). The transfer case in my car has always been noisy.

I think the early USDM drive trains were built loose leading to several problems but evidently the transfer will still hold up if not hammered too hard. As I say, going on 13 years.