Clutch LSD Oil Change Interval

marrawi

Thought I'd share my finding, it definitely was helpful to me, hope it will help fellow Z owners as well.

I have ATS metal LSD, clutch type, installed on my 2015 370Z. According to ATS instructions, any GL5 LSD oil will work but it has to be changed every 2-3k miles. I also called ATS to ask about change interval after events, I do autocross only now, they advised that I change it after every event.

In addition to the pain of changing LSD oil every other month, I have gone through the trial and error of trying LSD oils to find the best balance between longevity and noise (friction modifier additives). The first LSD oil I used was motul 90PA, which is mineral-based, first impression was excellent, made my LSD quiet as if it was carbon LSD. But it broke down rather quickly after 1200 miles and the LSD started making some noise (at low speeds, you know what I mean if you have a clutch LSD) and harsher engagements.

I then switch to 75W140 Royal Purple gear oil hoping that it has higher viscosity and it will make the LSD smoother. It was the exact opposite, extremely noisy and harsh engagements with that oil.

During that time, I changed my Evo 10 (which has 9k miles) LSD oil using OEM diaqueen 90 SAE LSD Oil. Searching the forums, lots of people swearing by that LSD oil compared to aftermarket ones. So I thought I'd give it a try. It is so far the best balance between noise, longevity and performance, especially since you can snatch a quart for $12 from MAP performance!

Now let's get to the oil analysis, I have Blackstone analysis of diaqueen 90 SAE virgin oil to measure at the additives, and then I sent another sample of the oil after two autocross events (not one as ATS advised). Blackstone technician probably thought I was crazy for changing the oil that frequently, especially since the oil was in pretty good shape. They advise that I try again after four events. Attached are both virgin and used oil for reference.

Next I will do three to four events on the LSD oil that I have right now, I will send another sample to Blackstone and will report back here.

changing LSD oil that frequently is not only cost prohibitive but it's also a pain in the ***. I do love my car and I like to service it, but with that much of service, it was becoming cumbersome as if I am caring for a special need Z. Excuse any typos as I'm posting this off my phone.

Attached Images

Mitsubishi Diaqueen SAE90_zpsdczihs9p.jpg (185.4 KB, 24 views)

Attached Files

2015 370Z-TR-181021.pdf (47.4 KB, 8 views)