Due for differential gear oil change...
 

Quick search suggests that the consensus preference is 2 qts of Redline 75W90 synthetic.

However, is this oil the appropriate choice for a VLSD???

I was under the impression that this oil is best suited to open diffs -- is this incorrect? I believe there is a variant without friction modifier additives -- would that be better?

Can someone with a good working knowledge of VLSD's confirm that Redline 75W90 (or a variant or another oil entirely) is the correct choice?

Several threads raise these questions, but don't seem to arrive at a clear answer, at least to me... :confused:

Also, any difference in the diff for the 7AT vs 6MT -- mine is the auto.

Plan to order needed fluids and gaskets as noted here within the next day or two...

Thanks in advance! :tiphat:

EDIT: Okay, further searching suggests that the regular Redline gear oil is preferred and that the diff itself is actually sealed (?).

Other suggested alternatives I've found include:


Lubro Moly Gear Oil Syn 75w-90 GL-5 Diff

Richmond Gear Oil Syn 75w-140 GL-6 Diff

Shell Spirax synthetic 75W90 gear oil.

Curiously, NONE of those are the same weight as the factory oil?

Huh?

Er... help?

I presume you read this already:

http://www.the370z.com/diy-section-d...il-change.html

Redline also makes 75-90NS but I have seen that more for trannies then rear ends (I use it in the Subaru for example, but the rear end gets 75-90 GL-5 gear oil).

I am a few years from needing this maintenance so I have not spec'd the fluid myself. I see it requires GL-5, and if its a sealed diff 75-90 should be peachy. Its rare these days to need modifiers and other items. If you are in doubt, go OEM.

In many cases, OEM fluids are absolutely fine. Some folks just feel 'smarter' not using OEM fluids. Few folks on the inter-tubes have the requisite automotive and/or mechanical engineering degrees and practice automotive lubrication and testing to respond authoritatively to the many debates on the subject :D

I have used OEM fluids for some applications...and in others aftermarket has been the ticket.

Enjoy the drive,

- b

Subscribed!!

:iagree:

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

Thanks for the input, guys :tup:

Question: Why don't people use the recommended 80W90 oil? Is it because people like Redline and Redline doesn't offer that viscosity, or is there another reason?

Did a quick google search on synthetic GL5 80W90 gear oils and found a few other alternatives:

Mobilube HD Plus 80W-90 Gear Lubricant

http://www.wolfoil.com/update/docume...ion/2312ce.pdf

Some details on different gear and trans oils here
http://www.widman.biz/uploads/Transaxle_oil.pdf

Suggests a GL6 might be even better? I will search for one...

Here we go -- what about this?
http://www.torcousa.com/technology/SGO.pdf

Castrol Australia - Manual Transmission Fluid

A paper by Amsoil people might find of interest (not independent, obviously, but still informative)
http://www.synthetic-oil-tech.com/Ge...te%20Paper.pdf\


Thoughts?

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

Apparently around 30K, though some like to do it sooner.

I'm still trying to figure out which gear oil to use... :icon14:

One thing to note is the fact that Nissan changed the rear diff recommendation from year-to-year....
Rear Diff: GL 5 80w90
In the 2010:
Rear Diff: 75w-90


The LSD is sealed. No need for a friction modifier, etc.


I imagine most people use the Redline because it is a good oil that gets good results. A slight difference in viscosity shouldn't/doesn't seem to cause any problems.

That's very interesting -- mine's a 2010, too -- although I doubt there's anything different mechanically. What parts of the diff actually get lubed if the LSD is sealed unit?

Okay -- I think that settles it for me then. I'll go with Redline.

Thanks! :tiphat:

I did it at just 14-15k and it was mud and full of metal deposits (normal from breakin I assume)... most people have the same experience. I plan on changing mine more frequently than they recommend.

So to summarize Red Line 75W90 GL-5 57904 Differential Fluid ..
But which one for the 7AT tranny? I just cracked 30K and I want to do both on my next schedule service.
Thanks

No need to do it -- non serviceable. If you want, check it around 60K.

No need to do the Tranny or differential?

If you mean no need to service tranny... then go with the Red Line 75W90 for the differential?

Thanks in advance.

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.