weird noise after installing wavetrac LSD

Zilver

Hi Guys

I really need your help to identify the cause of noise after installing Wavetrac Helical LSD for my manual 370z. I can hear some whirling noise that happens when car is moving but most noticeable when I go neutral to get rid of my loud exhaust noise. There was NONE of this noise before the install. It was installed by a transmission / diff shop.

The noise is like whirling that seems to reduce in frequency as RPM or wheel rotation slows down. Here are two videos I uploaded, the noise becomes very apparent when the gas is let off and put on neutral.

https://youtu.be/02HY-Ipzbvw
https://youtu.be/fiyJ_rl2vkE

The diff shop mechanic that installed it couldn't identify the cause so I went to Nissan and they concluded its backlash out of OEM spec by the indication that there is some play on the driveshaft. However the diff shop mechanic claims they did the install within the .13 to .18 of a millimetre for the backlash as per Nissan specification.

Diff shop mechanic is happy to cover the remedial cost if Nissan or another shop finds that the problem is really coming from installation fault. I want to be sure that that is the case before taking to Nissan to repair as its quite costly to take it down to see whether proper shimming is needed to fill the gap.

So i want to check with you guys:
1. what is the cause of this noise? Nissan said the noise comes from the play in the driveshaft, do you think this is true? If so could it be because the pinion and ring gear isn't in right contact / backlash?

2. what is my best step to minimise cost and remediate the problem? I already paid for the full install it pricey and want to avoid dumping any more money in when it should be set up properly in the first place.

Really appreciate everyone's advice on this matter.

Regards

fryzia23

My guess it’s not the backlash clearance that is the issue. The possible cause is the incorrect ring/pinion gear contact points/mesh. This is adjusted using shims at each side of the diff. When I did my own osgiken diff install I was within specs with factory shims. Some aren’t so lucky.

Spooler

First thing first. Did you get and install the correct stub axle? Watching the axle do the funky chicken it appears you did not replace the stub axle.

Spooler

Did you get one of those?

https://www.z1motorsports.com/z1-pro...13d75019290644

Zilver

I am not a mechanic so correct me if I am wrong in things I say and I don't know how to quote to reply so I will just do a @ name.

@fryzia23
Isn't backlash caused when LSD unit isn't placed properly inside the carrier case? So this could be one of the reasons the ring gear and pinion are not in proper contact with each other?

@Spooler
i have purchased a new stub axle as per Wavetrac's website to replace my old OEM VLSD.
Wavetrac® Differentials - Application List

It said "370Z with OEM viscous LSD must replace RH axle flange with Nissan #38220-JK01B (1 req) to install Wavetrac"
Just a side note I believe a open diff Z has stub axle JK01A on both sides and the VLSD version has JK01A on the right side and JK01B on left side. Wavetrac requires both sides to be JK01B that's why only the right stub axle is needed to replaced from JK01A to a JK01B for my VLSD.
My car is RHD but the mechanic has taken out and returned me a long stub axle which is JK01A .

I bought it from
https://cdn.z1motorsports.com/imageG...etailsHalf.jpg

I didn't notice until you told me that the left stub axle was doing the ''funky chicken'' however we followed Wavetrac and never swapped the LH stub axle. That movement is really weird indeed not perfectly rotating, is it normal?

fryzia23

This is a good explanation for mesh pattern using a paint designed for this application. If it’s not in good contact then the installer needs to make adjustments by shimming. It technically goes in one way. Also did you get new side bearings? And what gear oil what used?

Attached Images

E0212A13-4D87-4B63-8178-A1D2A4D1700D.jpeg (103.1 KB, 28 views)

Spooler

So he replaced it. Sounds like he didn't do something right during the install.

Zilver

Here is a video of me turning the driveshaft by hand, is this meant to move as its connected to the pinion inside the lsd case?
Can i ask a favour someone try to turn it? Is it normal or is it caused by backlash as per 2nd video 4:10 explained below
https://youtube.com/watch?v=Cl7kmAAdc9w&feature=share

This guy demonstrating backlash as he can move the pinion driveshaft without the crown moving or vice versa at 4:10
https://youtube.com/watch?v=RRX3tEuMecY&feature=share

Also the left stub axle has bit of play as well vs the right with less play, normal?
https://youtu.be/oEYhhZf0N4Y

fryzia23

That seems normal to me. There will always be some play when moving back and forth. Also you did not mention about bushings. Did you replace them? I have my car in my garage on the lift so I could make a video for you later tonight. I have OS giken diff.

Zilver

I got Motul comp oil and got new bearings and seals for the install.

Have installed z1 poly diff bushings when the diff was installed, i undrstand that could increase nvh but not sure here when noise is more mechanical?

Thx for that cheers

Zilver

Anyone tried turning their z's driveshaft and had the same thing?

Rusty

You will always get some movement at the driveshaft.

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