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