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Disclaimer: This is not a how-to guide, this is just how I did it on my 2017 Outback 2.5 Premium. I probably did a million things wrong, use this information as such. I'm posting this since I didn't find any other comprehensive walk-through for the non-dipstick differentials. You are responsible for your own safety, your own actions, and your own vehicle.

Capacities, fluids, torque values (for my 2017 2.5 with TR580 CVT and T-type rear differential)
Capacity (front): 1.2-1.3 qt
Capacity (rear): 0.8 qt
Torque Values (front): Drain Plug=51.6 ft-lb Check plug=36.9 ft-lb Fill plug = 36.9 ft-lb
Torque Values (rear, T-type): Drain plug=36.1 ft-lb Fill plug=36.1 ft-lb
Oil: I used Mobil1 75w90 front and rear. There is a thread debating what fluid should be used for the front diff. The consensus seems to be that 75w90 is fine up front, even though it is listed as an alternative. https://www.subaruoutback.org/forum...06842-front-differential-fluid-change-10.html


Tools:
2 ramps, 2 jack stands, floor jack
8mm hex bit (front fill and check plugs)
10mm hex bit (rear fill and drain plugs)
T70 torx bit (front drain plug)
10mm?? Socket (front under-cover bolts)
Flat head screwdriver (front under-cover clips)
Breaker bar, pipe, or some other means of leverage
Torque wrench

Supplies:
3 quarts of gear oil (you need ~2 for filling, plus extra that will get lost in the fill pump, or in case some gets spilled)
Gear oil pump
Plenty of rags
Brake cleaner
Drain pan

Raise vehicle
The first thing I did was raised and secured the vehicle. I knew I would be taking the front passenger side wheel off, so I backed the rear onto ramps then jacked up the front and supported the car with jack stands. There’s plenty of discussion here on supporting our cars so I won’t dive into that.

Remove the front under-cover
According to the FSM there are two different covers (I’m guessing for the 2.5 & 3.6). This image from the FSM shows the two types, mine was the left type.


There are 11 large push-clips (I think, I didn’t count until I replaced it), 6 small push clips, and 3 bolts (I think they were 10mm) to remove. The three bolts are easy to locate, and so are the 6 small clips (once you know they exist, 3 on each side). Most of the large clips are easy to spot, but there are 4 near the front jacking plate that are sort of hidden.





The front of the panel gets tucked above the front bumper, which assists with removal. I pulled all of the clips using just a flat head screwdriver to pop out the center plunger then pop out the clips. It might have been easier with an upholstery tool, but I was too lazy to crawl out from under the car to get it. With all clips out I removed the 2 front bolts, then supported the cover with my hand as I removed the 3rd (rear-most) bolt, which allowed me to slide the cover back a bit then remove it. There was a fair amount of grit up there, so I was careful not to dump that on myself.


Locate and remove the fill plug
First I located and removed the fill plug, since I didn’t want to drain the fluid without confirming I could actually refill it. The fill plug is on the passenger side of the differential, near where the CV shaft plugs in to the differential. The easiest way to access it is to pull the passenger wheel. It may be reachable from above, or from below without removing the wheel, but when trying to get at the plug from below the exhaust will complicate things. This was my first time attempting this job so I took the easy route of removing the wheel, which is really not a difficult additional step. For the record I will do it the same way at 60k, since this made accessing the plug super easy. See the pictures showing the fill plug location from multiple angles.





Pictures from above, under the hood, looking down all the way in the back near the firewall.






The plug requires an 8mm hex bit for removal. It’s in there pretty tight, so I needed a little bit of leverage to get the job done. I considered the impact gun, but quickly realized that was a big risk since the differential housing is cast aluminum. The fill plug gasket stuck to the differential housing. I managed to knock it loose later on, luckily I realized it at the time since I simply re-used the existing gasket. When I do this job again I’ll pry it off as soon as I pull the plug (and will likely replace the gasket too). The picture below shows how I positioned my tools to crack it loose.


Link for non-rotated version of above pic, not sure why the site is rotating it

Locate and remove the check and drain plugs
The check and drain plugs are much easier to locate since they are labeled. They are near the rear of the plastic under cover, just in front of the transmission pan. The check plug is an 8mm hex plug toward the driver’s side with “Check” cast next to it. I removed the plug and caught a bit of overflow with my drain pan. (Side note: The FSM states that you may have a bit of excess fluid come out when removing the check plug on the factory fill).



As a double-check to make sure I had correctly located the fill plug, I added a bit of new oil and verified that some oil then drained out of the check plug hole.

The drain plug is labeled “Diff Oil” and is a large T70 torx plug that’s pretty difficult to miss. Like the two other plugs, it was on there tight and required a bit of leverage to crack it loose. I pulled the plug and let the oil drain. Like others had previously mentioned, the front oil looked relatively clean. There was a small amount of black sludge on the magnetic drain plug which is normal, but no metal shavings/chunks etc. to indicate a problem.

Once the oil came to a slow drip I wiped up the drain plug area, made sure the gasket was in place, then re-installed the plug and torqued to spec.


Fill with new oil and replace plugs
I purchased this FloTool Transmission Fluid/Gear Oil Spout from Advance Auto Parts (I do not recommend this item!).
https://shop.advanceautoparts.com/p/flotool-transmission-fluid-gear-oil-spout-10106/89011612-P#
I planned to fill the oil from above (under the hood), holding the new quart upside down and letting it drain into the diff. This requires sticking the bottle in place from the top, positioning the tube into the fill plug from below, then going back up top to open the valve on the filler. As you can guess, this didn’t work well. The threads on the spout stripped so the oil started dripping from the bottle. This left me in a compromising position, unable to go down below to remove the tube and catch whatever would come out. In the end, I wound up with gear oil all over the side of the diff and on the catalytic converter (but, miraculously, nothing on the driveway).



So, on to the gear oil pump. I initially didn’t want to use it it because I would have to waste good oil to flush the pump (I couldn’t remember what it was last used for), and it also didn’t fit into the Mobil1 gear oil bottle. I wound up cutting the top off my first less-than-full bottle, dropping the pump in, and flushing a few good pumps of oil through it.


Link for non-rotated version of above pic, not sure why the site is rotating it



I placed the pump hose into the fill hole using the “grabbers” to hold the hose in place. Making sure my drain pan was still in place under the check hole, I pumped a little over a quart into the diff when a stream of new oil started to spill from the check hole . By the time I got under the car, took my gloves off, and snapped a pic, the stream slowed to a fast drip. I wiped up the excess, verified the gasket was in place, then re-installed the check plug and torqued it to spec.




I also wiped up around the fill hole, and after making sure the gasket was in place I re-installed the fill plug, torquing to spec. I wiped up all of the spillage then sprayed the affected areas with brake cleaner, again wiping up as much as I could. I made sure to give a little extra attention to the catalytic converter that got a bit of oil spilled on it.

Replace front under cover
After giving everything a once-over to make sure there were no leaking plugs and no missed spillage, I replaced the front under cover. I tucked the front tabs in above the bumper, and holding the cover in place I then installed the rear-most bolt. I then installed the 11 large clips (doing it again I would start with the clips near the front, since they were the most troublesome holes to line up), 6 small clips, and 2 remaining bolts.


Rear: Locating and removing the fill plug
The rear differential is much more straight-forward. There are three types of rear differentials: T-type, VA1, and VA2. Mine was the T-type, which has the drain and fill plugs easily visible from the rear cover of the differential. Both plugs are 10mm hex, and required a bit of leverage to remove. I began with the fill plug to make sure I could actually replace any fluid I drained.



After removing the fill plug and gasket I pulled the drain plug. Like others here, my rear fluid was much darker than the front. Again there was a bit of black sludge on the plug magnet, but nothing shiny or concerning.



I replaced the drain plug, being careful not to mix it up with the fill plug (drain plug has a magnet), and torqued it to spec.



I pumped new oil in through the fill hole, slowing as I neared 0.8 quarts. I stopped filling just as the new oil began to trickle from the fill hole. I replaced the fill plug and gasket and torqued it to spec. I wiped up the spillage, sprayed the area with brake cleaner, and verified there were no leaks.

I then replaced the front wheel, lowered the vehicle, and torqued the lug nuts tlo spec. Since I had the tool in my hands and set, I checked the rest of the wheels too.

Edit: fixed some pic spacing, added links for rotated pics.
 

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Wow, very detail write up, Thanks ! How easy for you to go up the ramp in reverse :)
 

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Discussion Starter #3
Wow, very detail write up, Thanks ! How easy for you to go up the ramp in reverse :)
Thanks. Way less stressful than going forward! Just stick your head out of the open door to see exactly where you are.
 

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This is a fantastic write-up. On my "to do" list at the next oil change, along with CVT drain/fill. Thank you.
 
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Wow..great details and would really help me in the future. I filled my front diff fluids through the overflow hole because I was too lazy :) but may consider removing the front, passenger wheel to access the fill hole in the future.

A quick question, how was the car stability on two ramps AND two jack stands? Any pre-cautionary measures?
 

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Wow..great details and would really help me in the future. I filled my front diff fluids through the overflow hole because I was too lazy :) but may consider removing the front, passenger wheel to access the fill hole in the future.

A quick question, how was the car stability on two ramps AND two jack stands? Any pre-cautionary measures?
Filling through the check hole is probably easier in the end, so long as you can get your fill tube in the right way.

Stability on the ramps and stands was fine, and IMO better than 4 jack stands, at least in my case. My driveway has a slight downward pitch toward the street, so I can never seem to get a car on 4 stands without one of them getting a little tweaked. However I suppose starting from the rear might help avoid this, I cant remember if I've ever tried that before.

As you can see I have some super heavy jack stands which worked nicely under the front control arm braces. I've yet to support the car near the pinch welds as recommended, just because I don't have stands that can sit at that spot without crushing the pinch weld. It looks like it may be possible to orient the jack stands the opposite way, again I've yet to try.
 

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Thanks!!! Really helpful. Maybe just me (or my Chrome browser) but can't see any of your pics... ;-)
 

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Thanks!!! Really helpful. Maybe just me (or my Chrome browser) but can't see any of your pics... ;-)
My Chrome browser didn't show the picks either. Looked on my phone it is fine. Oh and subscribed. I had the dealer do this at 60,000 miles. They also spilled oil on my exhaust system. :rolleyes: So don't worry about it @rlb81 ! I may try this next time now.
 
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Thanks!!! Really helpful. Maybe just me (or my Chrome browser) but can't see any of your pics... ;-)
That's odd, I can see them every place I've checked, even if I go in private mode (i.e. not logged in). The pics are hosted on dropbox, were you looking at work, and is dropbox blocked there?
 

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Discussion Starter #13
Very well detailed write up, but just wanted to add, I used this transfer pump from MityVac to fill diffs and it worked great.
Thanks. I like the looks of that pump, I'd imagine it's got graduated marks on it?
 

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Thanks @rlb81 for this HowTo! I wish I had seen this thread last weekend, the first time I attempted the front differential. Your picture on where to position the breaker bar to remove the fill plug was the key. I had tried it from the top and the wheel well (with about 3 extensions) before I gave up. Following your directions, I only needed less than a 1/4 inch rotation to break the fill plug loose.
 

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Thanks @rlb81 for this HowTo! I wish I had seen this thread last weekend, the first time I attempted the front differential. Your picture on where to position the breaker bar to remove the fill plug was the key. I had tried it from the top and the wheel well (with about 3 extensions) before I gave up. Following your directions, I only needed less than a 1/4 inch rotation to break the fill plug loose.
Glad it helped. I spent time piecing the info together, so I figured why not. Even though much of the info is the same as previous gens, I always find it helpful to have everything in one spot!
 

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This is a great write up. I'll be tackling the differential fluid change in a few weeks and this will be a big help!. How do you tell the difference between the T-type and the VA-1 type rear differential? I saw a couple of posts indicating that the VA-1 has a ribs on the housing, which it appears this one does (and mine too). The only other difference (external) appears to be that the VA-1 has gaskets in the drain and fill plugs while the T-type requires gasket seal. That's my real question: do I need to purchase new gaskets or just use gasket sealer?
 

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Thanks - I had seen this but it indicates that you only need new gaskets for the VA-1 type differential. The T-type only needs liquid gasket. So, if I can figure out whether I have the T or VA-1 I'll know if I need to buy gaskets before starting the job.
 
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