Nissan 370Z Forum - Due for differential gear oil change...

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- - Due for differential gear oil change... (http://www.the370z.com/nissan-370z-warranty-scheduled-maintenance-servicing-repairs/50170-due-differential-gear-oil-change.html)

Quote:

Originally Posted by joshs09slvrZ (Post 1564088)

When should this be done? I am just over 31k miles...

I plan on doing mine every 15,000 kms

The first time at 5000 kms it was a disgusting mess. Reports are that it needs frequent changes due to high operating temps. Plus it is a simple fluid change to do for low cost. Can't hurt.

Quote:

Originally Posted by wstar (Post 1587487)

Any quality synthetic 75w90 is gonna be fine in the diff. Personally, I like Royal Purple for my diff, but I doubt it makes a huge difference between the good vendors.

On the 7AT: the official Nissan stance is that the fluid inside the thing is good for life and never needs any changing. However, at a mere ~18K miles my 7AT fluid looked like it was about done for. Keep in mind I drive in a lot of summer heat and I use/abuse the 7AT pretty hard. I wouldn't think it's wise to go more than ~20-30K miles without changing out the fluid, unless you always drive it like a grandma. A little 7AT fluid every 20K isn't a big budgetary concern anyways.

Any quality Nissan dealership can do it for you, but you *do* need to use a dealership because only they have the Consult-III diagnostic tool to tell them the 7AT's internal temperatures to set the fluid level correctly. I really have no idea why Nissan went down this path of trying to make the fluid a "good for life" item, I can't even imagine an angle it makes sense from business-wise. It might have mostly been that this tranny requires the aforementioned precision refilling and they didn't want to say "You have to change this fluid regularly, but you can't do it yourself", so they opted for a very long-life fluid.

Keep in mind that I'm not trying to say that the fluid is good for 100K miles or anything, but I've recently read that you can't really go off the color of fluids as a judgement of how much life is left. What do yall think about that?

Quote:

Originally Posted by Corbitt (Post 1587717)

Makes sense since regular oil is the same way. People think just because the oil is dark/black that it's dirty or time to change. The only thing you can do is send it off for oil analysis to see just what happened to the oil.

$20 for peace of mind....

I'll change my oil.

Well the topic drifted to AT fluid above, hopefully everyone changes their oil :) When I say it looked bad at 18K, I didn't get an analysis done, but that wasn't just color either. You can feel the difference slipping the fluid between your fingers, between fresh Nissan Matic-S ATF and the stuff in my car. It's not real fluid analysis, but it's not useless either.

The only reason I even noticed is because I was installing an ATF fluid cooler at the time, so I had to buy an extra quart or two to fill up the new capacity, and disconnect the lines and see the old fluid in the install process. I did the cooler install at home by pre-filling the cooler core and most of the new line length, and being very careful about capping things off and minimizing spills during the hose hookups. And then I took it to the dealership for something unrelated a couple weeks later and had them swap the fluid and re-set the level perfect.

^^ good point also!!

I have used Amsoil and Motul... Probably amongst the top 3 for choices. I didnt notice a difference in one vs. the other but the motul was a little more expensive.
The Differential calls for GL5 oil where the manual trans calls for GL4.
Check the link below its direct from Amsoils site. They were the FIRST in synthetic oil and their stuff is great! I used in my engine, trans and differential and put in all my other cars as well!

AMSOIL Product Recommendations - 2010%7cNISSAN%2fDATSUN%7c370Z%7cM

Just sharing this, because I am pleasantly surprised:

After replacing factory gunk (which looked not too overly gunky, actually) with fresh fluid by Redline, less drivetrain vibration on hard shifts.

Am I imagining this!?

Anyway, glad I changed the fluid, placebo or no.

wth is a rear differential oil change? is there a dip stick? i know theres transmission oil, engine oil, brake fluid, coolant, battery fluid, windshield fluid, power steering.

but whats rear differential oil? and dip stick, can someone PM me, i may not get to see this again, might forget

The rear diff has a drain plug and a fill plug, and yes, it has a fluid that needs changing. It's in the service manual if you need details. The rest of the thread has info on fluid recommendations. Tracking the VLSD (yeah I know, getting rid of that's "on the list"...), the fluid definitely needs a regular change. I've been doing mine roughly every other oil change.

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Quote:

Originally Posted by TreeSemdyZee (Post 1562734)

Not sure what you should or shouldn't use, but I put the Redline in a few months ago.

Cheapest price I found if you're going that way:

Red Line 75W90 GL-5 57904 Differential Fluid - Nissan performance parts

Amazon has it for a few bucks cheaper including shipping:

Red Line 57904 (75W90) Synthetic Gear Oil - 1 Quart : Amazon.com : Automotive

that mt90 works AWESOME in my trans. I can now quick shift 1st to 2nd and not grind at all. A little thicker than what is called but works amazing thus far. I changed both diff and trans at 36k miles. Diff was really dark and syrupy, but thats about what the manual calls for in reguards to changing your diff oil.

Quote:

Originally Posted by roy'sz (Post 1946679)

Don't use MT90 in the differential!! You'll see right on the bottle!

Quote:

Originally Posted by 6MT (Post 1946741)

Don't use MT90 in the differential!! You'll see right on the bottle!

Yeah. The weight is close but you need a GL5 oil for the diff, badly needs the high pressure additives.

I didn't use mt90 on my diff. I used 75w90.