Just installed the 4.57 diff and having a few noise problems on road test.
Being in the UK I have no whereto go to compare whether the noise is correct or not as no one has done this modification in the UK yet as far as I know but I strongly suspect the noise I have is incorrect.

Symptoms:

The noise from the diff in certain driving conditions is quite bad and whether it will bed or not I'm not so sure.

The main gear/growling noise is only evident under "drive" conditions, no noise on coasting or really on over run, the main gear noise starts about 20mph and gets progressively louder to about 40mph, it then starts to get quieter to just a steady whine as you travel along at about 50-60mph (I

 

here's one problem that my mechanic ran into on my install. there should be a constant torque through all the teeth of the entire gear. i think it's something like 8-11 ft-lbs. well, on one part of the gear, it jumped up to about 25. it took him a while to isolate the problem, but there was one tooth with just a wee bit of marring. he took a file to it and put it within specs. he told me if he had not done so, there would have been a lot of whining.

 

wortham,

Can you post a picture to illustrate what he did for clarification?

Thanks.

 

hmmmm ... let's see if i can describe it cuz i really can't think of a way to either make or show a pic of it. basically there was just a tiny bit of extra material on the inside of the tooth. barely noticeable at all. he would take a small file to it to make it look like the rest of the teeth. he'd do just a bit of filing, check the torque, do a bit more filing, check the torque. he kept doing that til it finally fell into the tolerance.

it's important to point out that it was not anything you could really see all that well with the eye. in fact, it took him 2 hours just to find the tooth that was giving him problems. i guess the best way to describe it is if you see a paint job and there's just a wee lil spot of clear coat that ran. until you're right on top of it and know what you're looking for, you can't see it. but the tolerances inside the diff are so tight that i would have definitely heard the problem if he didn't stop to fix it before he was done with the install.

 

hmmm...

 

there are a number of posts going on around the 4.57's - have you scoped them?

 

I've seen and taken in info off them all, they all seem to differ in one way or another, nothing exactly like mine.
I'll end up re-adjusting by the look of things, I just thought that some one might be able to narrow it down to a specific point.

One thing thats not been told is, as I asked earlier, is the shim that adjusts the pinion depth thicker or thinner than the stock one in most of the installs?

 

NOISE IN DIFFERENTIALS

The drive and driven gears of a differential are called a "ring and pinion" These are two gears that consist of spiral teeth that mesh together to change the direction of driveline direction power to axle direction power. At the same time, they change the ratio of driveline speed.

When a new ring and pinion are installed they need to be setup with special tools by skilled technicians to insure long life and the most quiet operation.

However, when a request is made to lower the gear ratio for more power, the number of teth on the drive pinion changes to a lower number. when you have a lower number of teeth teeth on a pinion, it means there are fewer teeth in contact with the ring gear. This causes two issures - the resultant pinion is not as strong as a fast ratio because fewer teeth and the differential will now become noisier, again because of fewer teeth in contact.

Ratios of 3.73 and numerically lower are most noticeable.

This noise is sometimes not noticeble due to other conditions of the vehicle such as large lug tires, open or unrestricted exhaust, wind noise and a variety of othe factors.

On other vehicles, it can be extremely noticeable. These vehicles are vans, motor homes and other vehicles that have large open areas in back that are open to the driver's compartment

These noises are acceptable and are not a cause of worry.

Factory installed gearsets in many heavy duty chassis vehicles (1 and 1-1/2 ton) often are backed by a serice bulletin to confirm the above, meaning that not only ratio changes can cause noise problems but new vehicles as well can have noises in the differential.

D.D. Williams Equipment Co., INC. (my installer )

NOISE IN 4.57 GEARS

Please note: The 4.57 gears sets are a performance product, made by Richmond Gear specifically for the S2000. The extra strength of the gear teeth result in a gear whirring sound that can be heard on acceleration. While the sound is not louder than many of the other mechanical noises common to high performance sports cars like the S2000, the whirring sound is noticeable, particularly with the top up. While many performance drivers consider such sounds part of the joy of driving a high performance car, buyers who put a premium on the absence of cockpit noise might be dissatisfied with this whirring sound.

www.Ricks2k.com

 

[QUOTE]Stratocaster Re: Settings for 4.57 rear gear install confirmed

 

Biker1, I had a similar experience with my 4.57. Turns out that the carrier bearings were not tight enough. Took it apart yesterday, torqued the carrier bearings to 50 ft-lbs, and presto, the noise is gone. Now, I only have a slight whirring sound that seems to be characteristic of this setup.