Orpheus

Hi

Spent the last hour or so looking through differential noise threads, but none seem to be exactly the same thing I'm experiencing, so I figured I'd just ask....

I went drifting with my car ('02, stock AP1 diff, AP2 transmission, Spoon engine/transmission mounts, J's Racing SOLID differential mounts)--did a bunch of mid-speed, "clutch kick" induced drifts. Also did doughnuts for 1/2 hour or so.

On the way back home, I noticed a new sound. Now granted, my car is really loud inside already due to the solid diff mounts. It is normal to hear "gurgling" sounds from the diff, along with a slight humming, and a bunch of other noises I've grew to ignore.

However, now I hear upon deceleration, like during a decline or coasting, a whistling noise from the rear. It's pretty loud relative to all the other noises.

As soon as I get on the gas, it goes away!

Also, can't really hear it < 40mph. Gets progressively louder from 50 mph on up. At 70mph, it's pretty loud.

Pushing in the clutch does not reduce the noise, nor engaging in neutral. Does this eliminate the transmission as the source of the noise?

I read this thread:

https://www.s2ki.com/forums/index.php?act=S...22&t=674603&st=

SpitfireS at the bottom writes something about changing flanges during AP1 -> AP2 transmission swaps. Well, I recently did that about 2 months ago. Could this bolt have come loose that he's talking about?

What do you guys think?

SgtB

It's on it's way out. Clutch kicks and doughnuts are the death of these diffs. Drain the fluid and check for chunks.

Bugs2k

a fractured ring gear can make a whistling or roaring noise.

chris_barry

My psychic diagnosis is that the pinion is riddled with cracks and very close to letting go.

If it lets go it will be more expensive. Jack the car up and put it on stands for safety. Drive it so the rear wheels spin and use a screwdriver or rod against your year to listen to the diff and rear of the gearbox. If its coming from the diff, time to fit a new crownwheel and pinion.

I had much the same noise, and when I pulled it apart the teeth on the pinion were peeling away like petals on a rose bud.

lotus7racer

"I went drifting with my car ('02, stock AP1 diff, AP2 transmission, Spoon engine/transmission mounts, J's Racing SOLID differential mounts)--did a bunch of mid-speed, "clutch kick" induced drifts. Also did doughnuts for 1/2 hour or so."

Do you guys consider this abuse or normal?
Just asking.

Saki GT

This is not normal use.

Orpheus

hi, thanks for your answer...

sorry, not too proficient at the technical stuff back there....

this crownwheel and pinion--is it part of the diff assembly? if i bought a used diff, would it normally come with this stuff?

I assume this is part of the diff as well?

S2KPUDDYDAD

It sounds like a loose pinion
The preload on the pinion bearings is lost that is why you can modulate the sound by letting on and off the gas. It is going to pop in short time if you continue to drive the car.
At this point you could very well have cracks in the pinion as posted by chris_barry. A repair can be made by replacing the factory distance piece (crush sleeve) and then resetting the pre load on the bearings. If the pinion already has stress fractures then, you will need a new (gear set) ring and pinion.

zzziippyyy

Its gonna go boom, dont stray to far from a wrecker..... but than again when you abuse it like that what did you expect?

chris_barry

I would drive very gently to a diff specialist. The technical term you want to use is "Failed Under Continuous Testing" or FUCT.

I would put a Mazda/Miata 1800cc 4.1 crownwheel and pinion in . They are cheaper than the Honda ones, bolt straight in, have better finishing on the base and edges of the teeth and seem to be a different material or heat treating.