despite whatever disagreements you may have with me personally, that is such a load of bull and you know i.

otherwise i guess every diff manufacturer should advertise that their plated diffs are "silent" "won't chatter" and "will make you forget there's a differential" because consumers "should have known" that clutch type diffs will be loud regardless of what they claim. there is a term for that ..

if the diff is going to be loud, fine - but don't claim that it isn't, especially as a major point of attraction on all promotional language.

 

In my experience, if I was concerned about noise I'd forgo any clutch type diff. It's one of the big reasons OEs use gear type diffs in most vehicles that have limited slips and I can't think of a single car that comes from the factory with a clutch type front diff.

Some of their wording definitely seems misleading but there's always a give and take with diffs, you'll never get to have your cake and eat it too.

 

to be clear, i'm not talking about noise - i'm talking about violent clunking that reverberates through the entire car. i'd say the wording is a little more than misleading.

in my own personal experience, i've had roughly half my clutch-type diffs make zero noise - all with the same fluid (red line gl5 75w90, except the front obviously):

- cusco 1.5 type rs: made a lot of violent clunking from the rear diff, rear felt basically locked
- had the cusco rebuilt with less of the preload springs - zero clunking or noise after, but still felt locked on throttle
- os giken 1.5 way - zero noise or clunking, likely due to the negative preload springs
- ats carbon-hybrid rear 1.5 way - zero noise or clunking
- ats carbon-hybrid front 1-way - violent clunking from front.

anecdotally, i've heard the tre 1.5-way may make some clicking noise, but after that, no noise as well.

 

something minor to note: after doing my figure 8s, i flushed the fluid. the rear diff came out black, with wear particle as expected. the trans and t case came out looking new, which is odd

 

Post 30-minutes of circle 8 - no improvement to the clunking. It's louder in person than in videos, and you can feel the force pulling the steering wheel as it clunks.

Talking with them to see if they have softer preload springs, but their responsiveness has been poor.

 

FYI - ATS thinks it is due to the gear oil, and that the diff should be silent.

I guess they are also unaware that the trans and diff share oil on the Evos, not t-case and diff.

 

Youre on the GL5 redline fluid now, try out MT90 which is a GL4. A little less gear protection but we arent drag racing here.

 

@Dallas J I've got MT90 in the gearbox, GL5 in the t-case. Or were you sayign to use MT90 in the t-case?

 

Oh, I thought you had 75w90 or 80w90 from another post in the front diff. Def not MT90 in the T-case.

 

i ran mt85 in the trans but never gear oil. i'm starting to wonder if that's exactly the issue with our front diffs clunking though. my ats rear diff is silent.

obv gl5 is much slipperier than gl4, too slippery for the synchros - but may be what the differential needs to not clunk

 

The 75w-90 NS is the non-slip GL-5 trans fluid (the reg stuff has 5% by volume friction modifier) and in my experience will make the clutch diffs chatter like crazy. Even a stock diff rear diff is super loud with it compared to running OEM or non-NS fluid.

I have extra friction modifier in the rear diff, about 7-8% to calm it down but in the front its not an option. So I wouldn't switch to a GL5 if you are already MT90 (GL4), it just going to get louder.

 

What is it about the MTL/MT90 cocktail that's so famous for quieting things down.

 

GL5 is not "more slippery" it simply has more extreme pressure additives. The only think that makes them slippery is when friction modifier is added, but the NS fluid doesn't have this.

LOL... a ****ing diff manufacturer doesn't even know where the diff gets its fluid from. Looks like I won't be buying anything from ATS...

 

People bought into the marketing. All it does is make MT85, which redline now offers, because technically the stock Evo8/9 trans fluid is 75w85. So MT90 is slightly thicker than stock.

 

that's what red line said, but you are probably right - GL5 is not more slippery inherently but may have friction modifier in it as "standard," hence the NS version without it.

what's surprising about ATS not knowing where the fluid is coming from is that I can't imagine this is an unusual situation for FWD cars - where the LSD will more frequently share the fluid with the transmission. In that case, I don't imagine they are recommending GL5 fluid here also, though I guess all transmissions are different. I think most hondas use synchromesh, not sure what kind of properties that has.