I posted also in the Under the Hood forum but I need an answer asasp so I'm posting here also.

Some background about the car, it has 17,000 miles and is stock.

The problem I get is when I turn the wheel (doesn't matter left or right) all the way till it locks and accelerate slowly in 1st gear and I hear a humming noise inside the cabin, I can't tell if its coming from the front or rear of the car.

I tested if it was my steering, so I accelerate slowly and put the gear in neutral and turn the wheel all the way till it locks and the humming noise isn't there.

Anyone experience this?

 

Its probably the diff groaning.....scared the crap out of me when I was new to the s2k scene. Its just the diff doing its job.

 

I had that noise too when I first got my S. I changed the diff fluid and the sound went away.

 

I was going to check the diff fluid and change if it needed to be but didn't have time today. Thanks for the feedback I feel a little less paranoid now.

 

Its not your fluid. I have a bone stock AP1 w/19K miles with new fluid-no change in sound. Its the diff doing its job. Full lock, either direction, forward or reverse in slow speed. Think about it this way...what is happening is one wheel is moving at a different rate than the other.
This was posted about last month or so ago just don't remember under what forum or topic.

 

I also hear it sometimes, though it's real faint. < 3000 miles.

 

I'm surprised dealerships haven't been getting this complaint, I called 2 Honda dealerships and they were baffled, I guess people haven't noticed.

 

The S2000 has a Torsen diff.
Torsen = Torque Sensing.
When driving around tight corners the outside wheel covers much more ground then the inside wheel.
In that situation the Torsen diff is "working hard" to allow both wheels to turn at different speeds WHILE delivering equal torque to them.
"Working hard" => humming noise => perfectly normal
Usually a difference in wheel spin means one wheel has lost traction and then the Torsen diff sends the torque to the other wheel, so you keep going forward.
At slow tight turns with slight accelaration both wheels can handle the torque (no slipping, lots of grip) but there IS the difference in wheel spin (by covered distance).
Mixed signals.
Torsen At Work

 

well explained