Rear differential fluid-2016 Subaru Forester 2.5

[SubieRubyRoo]

Originally Posted by T-Stick
Thinking about this more ... I don't think I would personally use Motul in a long drain application. I know they previously recommended a 30k change interval and I doubt if they reformulated everything. Setting that aside, I do not see info saying that they are specifically formulated for long drain intervals either. So if it were me I would at least use a long drain formulation gear oil in the front diff because they can be fun to change.


Please, do tell: what is a "long drain formulation gear oil", and how could something that is not as robust but has a "long drain formulation" last and protect any longer than the Motul formulation? Just wondering... maybe I'll learn something new.

 

[SubieRubyRoo]

100% synthetic ester, GL 4 & 5 rated along with a MIL spec.... I'm pretty sure it's good for more than 30k.

 

[UG_Passat]

Originally Posted by SubieRubyRoo
100% synthetic ester, GL 4 & 5 rated along with a MIL spec.... I'm pretty sure it's good for more than 30k.


Meeting MIL-L-2105D is misleading..
75w90 is not an approved multigrade weight according to the spec. So, it cannot meet the MIL-L-2105D, so that is false advertising.

That spec had a qualified products list, but since the spec is cancelled, there is no list.

Putting the MIL-spec on it is just to full people to think "Hey, it meets a MIL-spec, it must be good"

100% synthetic ester is also misleading, people will think it's a 100% ester base oil, which it is not.
according to its MSDS, 25% to 50% of it is Decene-1, an alpha olefin. 10% is olefin sulfide, an EP additive.

 

[Jmoney7269]

Everything I read about Subaru owners they love the motul gear 300

 

[ChiTDI]

I do the front and rear dif annually on my '14 Outback.
Factory fill was ugly the first year, and the breaker bar was a necessity.
I got a sale on Mobil1 75w90 and have used it exclusively. One and a half qt. for the front and .8 for the rear, easy job.
I do feel a difference after the work, and there is absolutely no noise. The fluid "looks" used when it's drained.
"Severe" service. Is there any other kind?
Interstate driving at 70+ mph for hours, rolling through snow banks, mountains in winter, desert runs in 100+ temps, I'm glad I don't live in those diff boxes!

 

[SubLGT]

Originally Posted by racin4ds
I've wanted to change the rear diff fluid on my 08 Legacy GT (with the LS) but cannot for the life of me get the drain or fill plugs loose! I gave up!..


Try something like this:
http://www.thetoolnetwork.com/square_drain_plug_socket_set.html

Quote
Three 1/2 drive sockets for those square drain plugs on those Japanese transmissions & differentials - 10m,13m & 17m. These sockets will help anyone who struggles with Japanese cars- especially Nissan and Subaru. These are Japanese Domestic Market products so represent the highest standards of quality. Their precise fit will eliminate stripped drain plugs caused by poor fitting tools

 

[BufordTJustice]

Originally Posted by ChiTDI
I do the front and rear dif annually on my '14 Outback.
Factory fill was ugly the first year, and the breaker bar was a necessity.
I got a sale on Mobil1 75w90 and have used it exclusively. One and a half qt. for the front and .8 for the rear, easy job.
I do feel a difference after the work, and there is absolutely no noise. The fluid "looks" used when it's drained.
"Severe" service. Is there any other kind?
Interstate driving at 70+ mph for hours, rolling through snow banks, mountains in winter, desert runs in 100+ temps, I'm glad I don't live in those diff boxes!


I acquired my 2011 3.6R Outback and dropped the diff fluid front and rear at 91K with Lucas 75w-90. Mistake; FE went down and diff temps with my IR thermometer went up slightly. Thickest "75w-90" I've ever seen. Dropped that after 4k miles for the std Mobil 1 75w-90 NS silver bottle at Wally World and everything went back to normal. But, I was surprised at how dirty the Lucas looked when I drained it. So, some cleaning occurred and that made me feel like the interval wasn't a total waste. I've been very happy with the cheap Mobil 1 NS stuff. I use Delvac 75w-90 in my 911...total overkill for the Suby.

Last trip to the Suby Dealer for airbag recall, I asked the techs what they used to service diffs and they told me the std Mobil 75w-90 NS silver bottle like you get from Walmart. Not one of them had ever seen a diff issue using that....even for those who tow or offroad. Anecdotal, but I think your recipe works great. Your diffs will outlast the rest of the car.