2014 Subaru XV Hybrid FF Front/Rear Diff 75W90 25k

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Factory Fill UOA from Blackstone at approximately 25,000 miles for front and rear differentials on XV Crosstrek Hybrid, driven mostly highway miles between 70 to 80 mph, with elevation generally between sea level and 2000' altitude, with some mountain driving in the rockies (elevations of 10 to 12k). Drained and replaced with Valvoline Synthetic GL-5 75w90.

Does not appear to be Subaru Extra S - more similar to the Subaru HPGO VOA posted here: http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3542880/Re:_Subaru_High_Performance_Ge

Front Differential Results

AL.....................5
Chromium..........2
Iron..................183
Copper..............1
Lead.................0
Tin...................0
Moly.................1
Nickel...............1
Manganese........19
Silver................0
Titanium...........0
Potassium.........0
Boron...............82
Silicon..............144
Sodium.............5
Calcium............20
Magnesium.......2
Phosphorus.......1240
Zinc.................16
Barium.............5

SUS@210 F.........56.1; should be 67 to 80
[email protected]; should be 12.2 to 15.18
Flashpoint..........410; should be >370

TAN 2.6

Rear Differential Results:

AL.....................4
Chromium..........6
Iron..................475
Copper..............53
Lead.................0
Tin...................3
Moly.................1
Nickel...............1
Manganese........30
Silver................0
Titanium...........0
Potassium.........2
Boron...............72
Silicon..............13
Sodium.............2
Calcium............9
Magnesium.......2
Phosphorus.......1351
Zinc.................18
Barium.............11

SUS@210 F.........60; should be 67 to 80
[email protected]; should be 12.2 to 15.18
Flashpoint..........420; should be >370

TAN 1.8

Full reports posted in JPEG (but small size may be difficult to read) at: http://www.subaruxvforum.com/forum/engin...ntials-25k.html
 
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Thanks for sharing.

Just yesterday I was considering if I should change differential fluid in my '13 Outback at 60k miles, or wait. I already drained the factory fill at 30k miles, and filled with Mobil 1 75w-90, and as many other Subaru owners have commented, I noted how black/silverish the drained oil was. And I wondered if the color was because of additives. There doesn't appear to be anything in your UOAs that would account for the color.
 
I replaced front and rear diff fluids in my 2009 Forester at 45k miles. It was nasty. Refilled with Redline 75w90. Might try their shock-proof next time.
 
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Sorry to be a new be herebut how do those look? I just bought a 2015 forester and was wondering if I should change it before then or if that still okay
 
Originally Posted By: Phishin
I replaced front and rear diff fluids in my 2009 Forester at 45k miles. It was nasty. Refilled with Redline 75w90. Might try their shock-proof next time.


Really? I changed the front and rear diffs on my '09 Forester at around 45k-50k miles, and the looked like clean new fluid coming out. I remember being surprised, because it really looked like new oil coming out, but I had owned the vehicle since new and had done all the maintenance on it myself, so I knew it was the original fluid.
 
I had a shop I trust do first differential fluid changes on my '02 Forester about six months after purchase -- I bought it used in 2010 with 90K miles. Not sure what fluid looked like. Had them use Valvoline gear oil I purchased. Then I did it again myself at about 125K (9 months ago) using same Valvoline oil. Drained fluid looked really nice. Hardly different from virgin. I did not perform analysis though. The good news is that performance was great before and after fluid changes.
 
The rear diff oil looked pretty bad - black, thin etc. Front diff still looked pretty good. I'm surprised they both sheared below the 75w90 specs.

I will check the rear again in 15k and maybe upgrade to Amsoil 75w110 or Motul 300.

Is anyone else surprised at the shearing? I would not consider my driving as "severe" schedule since it is mostly highway, although a few trips to Colorado and a few cold days during winter.

If I knew what I know now, i would have changed both after about 5 to 8,000 miles to get rid of the wear metals. Especially the rear diff which is only .8 quart capacity.
 
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Originally Posted By: hansj3
Sorry to be a new be herebut how do those look? I just bought a 2015 forester and was wondering if I should change it before then or if that still okay


Based upon my experience, and that of many Outback owners that have posted on www.subaruoutback.com, I would recommend a drain and fill of the differentials at 30k miles.

Almost every report I have read have reported oil condition similar to what SDS911 reports - fairly clean front differential oil, and very dark/silvery rear differential fluid.
 
Maintenance is 30k miles, 15k severe service or did they change that?

Probably used some borderline low viscosity fluid for mpg testing.

I would be surprised if the redline shears anywhere near as bad.

motul gear 300 is also great.
 
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XV Crosstrek manual recommends a "check" at 30k, but not necessarily a drain for normal schedule. Based on the UOA, I would drain much earlier after break-in. If you replace with a quality synthetic won't necessarily need to change for 30k to 60k miles after that initial drain and re-fill. But, I will be checking the rear since it is a smaller capacity and definitely had more wear than the front diff (both via the UOA and visual inspection of the magnetic drain plug).
 
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Does the front diff hold much more lube than the rear? The difference in iron between the two diffs is significant and you mentioned the difference in appearance.

Thanks for sharing!
 
Yes. Front Diff is about 1.4 vs. .8 for the rear (quarts IIRC). So, it makes sense the front looked better -- but both still sheared out of grade -- so my question to the experts here is whether that is normal given the mileage and driving conditions?
 
1. Stick with 75W-90. No need for anything heavier.

2. There is no need for an ultra-robust oil like Redline's Shockproof. Even for my previous STI with a limited slip Torsen-type rear-differential, Redline did not recommend it based on my driving style (aggressive, but not severe.) They recommended their light-weight or their regular gear oil.

For a light-duty (low power) open-differential, like the one in the N/A Subarus, I'd stick with a good synthetic and not worry about anything overly thick or robust. It's just not necessary, IMO.

3. The front differential, at least in my Forester, holds ~ double the lube of the rear.

4. Motul Gear 300 is pretty the best gear lube there is, at least on paper. Super high VI and great specs otherwise. I ran this in my rear diff on the STI and it was fine. I changed it to Mobil 1 and that was fine, too. I couldn't tell the difference, though I'm sure there might have been some difference.

I plan to change the front and rear differential oil twice in our FXT and never worrying about it again - once at 30k with an OTS synthetic, and then again at 60k with something more exotic, even though it's probably overkill. I don't plan to ever touch it again after that.
 
I expect much better results on the Valvoline Synpower 75W90 now that the initial break in metals are gone. But, for 3 quarts at $6.99 from auto zone on sale, can't go wrong with changing it out at 30k intervals. I'll check the rear diff again in about 15k just to see what it looks like and maybe send in another UOA sample. That will be in about 4 to 6 months at the rate I drive.

May have some Mobil 1 Delvac 75W90 Synthetic left over from my other car MT oil change to use in the rear diff next time.
 
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Shockproof is overrated for a daily driver, and its buildup(calcium)could upset the normal lubricant flow. Stick with GL5 gearoil.

What is required? GL5's are available in 75w80 and 75w85 also. Or, the lowest bid factory is junk that should be changed out quickly after break in.

Front/rear diff capacities?
 
Rex, you have made a great choice. Schaeffers 75-90 is run in thousands of farms,semi's and dirt tracks across the USA.

Schaeffers micron moly and penetro combined with great base stock make this a most excellent gear oil. Run it with confidence!
Schaeffers 293 75-90
 
Originally Posted By: sds911
Factory Fill UOA from Blackstone at approximately 25,000 miles for front and rear differentials on XV Crosstrek Hybrid, driven mostly highway miles between 70 to 80 mph, with elevation generally between sea level and 2000' altitude, with some mountain driving in the rockies (elevations of 10 to 12k). Drained and replaced with Valvoline Synthetic GL-5 75w90.




I was very surprised about numbers of rear diff:
Iron..................475
Copper..............53

What's wrong?
 
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I am very surprised with difference of silicon : 140ppm in front diff and 13ppm in rear diff.
Why?

Do you have the next UOA?
 
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