Differential howling / whining == $3000? (help?)
The center console area is nearest to the transmission, and has the least amount of sound deadening material, so all the drivetrain noise gets amplified through there. It could be coming from the front, the back, or the tranny itself.
I dont really hear of stock SC's blowing diffs left and right, or having problems with them leaking all over the place and locking up. It could be just a worn bearing...could be many things!
Rule out the smaller items first--
When was the last time you serviced the tranny and diff gear oil?
When was the last time the clutch was replaced? Were new bearings and seals installed? Are they leaking?
Does the car shift properly? Is the shifting notchy, or occasionally grinds on either upshift or downshifts?
Do you do a lot of standing drag launches, or tail-out drift jackassery?
Don't spend thousands on a hunch that may wind up not fixing anything.
- 20-25 whistle that increases in pitch as I accelerate (decreases as I decelerate), and then dissappears outside of 20-30 mph
- 40-45 whistle that sounds the same
The noise doesn't seem to be related to gears and seem to be worse when I'm coasting rather than accelerating or decelerating.
When it's really whining badly there's also a much quieter associated whiring that seems to increase with speed. It's as if there's always something rubbing, and very occasionally it hits a harmonic pitch and creates the loud whine (sounds like a whistle increasing in pitch).
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I dont really hear of stock SC's blowing diffs left and right, or having problems with them leaking all over the place and locking up. It could be just a worn bearing...could be many things!
Rule out the smaller items first--
When was the last time you serviced the tranny and diff gear oil?
- Around 12 months ago for each (last time I was having this problem I asked for them both to get replaced/topped up). They redid the diff oil when they replaced the diff
When was the last time the clutch was replaced? Were new bearings and seals installed? Are they leaking?
- Not sure, it's an SC400 so no clutch.
Does the car shift properly? Is the shifting notchy, or occasionally grinds on either upshift or downshifts?
- Shifting seems fine
Do you do a lot of standing drag launches, or tail-out drift jackassery?
- No, unless my car is whining -- then I go nuts.

Don't spend thousands on a hunch that may wind up not fixing anything.
- Great advice. Advice to live by with the local lexus mechanics.
it was the spyder gears in the diff that went.
when they broke, they locked up the driveshaft, and broke the imput shaft of the trans, and the sprag inside the trans.
Also i broke it when the car was stock. only an exhaust.
Forget the stock SC400 diff. Suprastore.com has torsen LSDs for $199.
If it breaks, it will destroy the trans too.The torsen diff is very strong
it was the spyder gears in the diff that went.
when they broke, they locked up the driveshaft, and broke the imput shaft of the trans, and the sprag inside the trans.
Also i broke it when the car was stock. only an exhaust.
Forget the stock SC400 diff. Suprastore.com has torsen LSDs for $199.
If it breaks, it will destroy the trans too.The torsen diff is very strong
While the swap in differential seemed to help the problem for around 8 months it seems to be back again *exactly* the same as it was before.
t.
Scott
the sound is most noticiable when the car is probably travelling less than 15mph and coming to a complete stop.
or u can also hear it if u are in D and then on level ground take your foot off the brake, as the car moves forward by itself (u don't have the push the gas) it starts making that whirring sound.
can anyone explain where this sound is coming from?
i looks like many ppl have brought this problem to the dealer but they did not post a reply as to the solution or where the sound was coming from.
thanks
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