2015 Subaru Outback 3.6 CVT reseal

[D60]

Most likely I'm facing a reseal of the front cover on a '15 TR690. Vehicle only has 97k freedom. Apparently not uncommon per Subaru TSB 16-103-16.

Anyone have tips, gotchas, or specialty tools I should source? Seems straightforward but real world experience is always good.

Also, should I pony up for Subaru's sealant or just use Right Stuff or similar?

Here's a high speed vid of the process once transmission is out:


(I do have the owner inquiring about the extended 10/100 CVT warranty under 16-107-17R, but with a door jamb placard of 2/15, coverage in 3/26 seems unlikely)

@Trav @CarbonToast

 

[Trav]

I am not familiar with that particular application but for aluminum castings on aluminum case I have had the best results with Permatex anaerobic sealant 51813 and Elring EL-Liq 74. IMO RTV blows, even a small excess ends up it places it shouldn't. Subaru lost a lot of engines with main bearing failure because of it.

​

 

[CarbonToast]

Mine is still leak free using Grey Permatex The Right stuff. I would use it again. Apply it, spread it thin, then assemble.

For your job, if working on jackstands, I would consider removing the engine and doing the front cover standing in the engine bay.

I have never done it but the service manual makes me think engine out the top is a quick job. No fighting the axles, dropping the exhaust, drivehsaft.

With the engine out, the added bonus is change the spark plugs, valve cover gaskets super easy and if needed reseal upper oil pan and timing chain cover. (Im looking at all those in the near future)

*i see it is an 3.6 maybe engine out is harder.

 

[nthach]

Toyota calls for a red RTV, FIPG 1281, made by ThreeBond. It’s supposedly resistant to ATF and gear oil, and the add pack in a CVTF isn’t too much different than ATF. Mopar also calls for an ATF-resistant RTV. Subaru calls for their gray stuff but if it was me, use the Toyota stuff.

And to @Trav’s point, I’ve used Loctite 518 to seal the oil pump on a Subaru EJ25 series engine with great success. I wouldn’t mess with RTV at that juncture.

 

[The Critic]

If Subaru calls for RTV, there could be a reason for it. Perhaps the required gap fill is too much for anaerobic to handle.

 

[Trav]

If Subaru calls for RTV, there could be a reason for it. Perhaps the required gap fill is too much for anaerobic to handle.

Usually if it is a clearance issue manufacturers will use a gasket. Subaru still specs RTV for the oil pumps even though that was the cause of many bearing failures. Oil pump screws on the rear of the pump coming loose and backing out is a long time well known issue and easily corrected with red loctite yet they still install them dry to this day.

Manufacturers seem to have a corporate mentality of not learning from their mistakes. An article on RTV.

RTV lawsuit

 

[The Critic]

Usually if it is a clearance issue manufacturers will use a gasket. Subaru still specs RTV for the oil pumps even though that was the cause of many bearing failures. Oil pump screws on the rear of the pump coming loose and backing out is a long time well known issue and easily corrected with red loctite yet they still install them dry to this day.

Manufacturers seem to have a corporate mentality of not learning from their mistakes. An article on RTV.

RTV lawsuit

RTV works perfectly fine and lasts longer than a gasket if properly applied. You hate RTV, we get it, but you shouldn’t be advocating for someone to go against OEM repair instructions (if applicable) on a high labor repair.

 

[D60]

I do find the conversation intriguing as I was just recently researching anaerobic. It seems really cool (yeah I'm basically 16 years old at heart -- oh gotta go I saw BOOBS!!!!).....

.....OK I'm back (no luck with the boobs BTW) and Permatex has a horrendous vid where they talk about their basic anaerobic -- which Trav reco'd -- vs the "high temp" anaerobic. My main takeaway was that the former is good for gaps to .015" and the latter .020". I'm no expert but a 20 thou gap on a sealing surface is pretty large.

ANYWAY, Mr Video Guy says it's not ok for aluminum, it is ok for aluminum, it shouldn't be used to dress a gasket, it can be used to dress a gasket. If they cared, they'd pull this video and start from scratch. PSA: just read the product instructions and don't believe anything Permatex says here (check comments for better, factual info)


I've always been interested in anaerobic since I learned GM uses it on all their IFS pigs at the seam. But, those are two machined surfaces and gaps should be probably well under 1 thou I'd hope. Also I think I understand why they'd use anaerobic: the fit here is critical and any gaps or any flex changes carrier bearing preload and thus gear pattern.

Anyway, being that I'm white trash I'm inclined to use Right Stuff here. Do we have credible data that CVT ATF will somehow degrade Right Stuff?

 

[CarbonToast]

Check out this TSB. Specifies threebond 1215.

https://www.google.com/url?sa=t&sou...YQFnoECCcQAQ&usg=AOvVaw3zWnT58nhNLPQzl2ATkacx

 

[Trav]

RTV works perfectly fine and lasts longer than a gasket if properly applied. You hate RTV, we get it, but you shouldn’t be advocating for someone to go against OEM repair instructions (if applicable) on a high labor repair.

You never disassembled a job only only to find a soggy mess of RTV? You are correct about me hating RTV, over 50 years of experience and proven it to be a mediocre product in most cases and the root cause of many leaks and failures and it is certainly not better than a quality gasket eg Subaru and others use RTV on their transmission pans, it works fine but it is a lot of work to remove the pan and residual stuff.
Some cars like GM used a high quality steel core laminated gasket that was reusable with none of the headaches associated with RTV.

I do use RTV if there is no alternative like a stamped steel pan on an aluminum or iron block, the steel pan is not rigid enough for another product and no gasket available so you are basically stuck using this RTV like it or not.
Manufacturers that spec RTV are motivated by ease of robotic application and later service, eg I am in the middle of a piston job on a CAEB engine that uses RTV on the oil pan and timing cover, both are cheap stampings that get damaged removing them, reusing them almost guarantees a leak. The manufacturers instructions are to replace the tins and bolts and use their special RTV sauce for a total cost of over $500 in OE parts. I do not and never have recommend products I have not had experience with that have proven to be a quality repair sometimes even going against the manufacturers recommendation.

Did you read the article? Why would anyone follow the instruction to repeat using a product that caused so much damage and expect a different result. Rant over. LOL

 

[D60]

Check out this TSB. Specifies threebond 1215.

https://www.google.com/url?sa=t&sou...YQFnoECCcQAQ&usg=AOvVaw3zWnT58nhNLPQzl2ATkacx

Interestingly, that doesn't seem to direct you to remove the second, larger cover to reseal it. It speaks only of 7 bolts, which is the smaller, forward, chain cover.

However I personally would absolutely do the larger, back cover also. It's just 5 more bolts and it pulls away. This high speed short covers it, and he does do both covers.

Maybe I'm mis-reading the TSB -- wouldn't be the first time! It reminds me of a Toyota 3.0 where I replaced the RMS but didn't pull the seal carrier to reseal it. The leak was still horrendous, so I learned my lesson there!!



Also I'm too chicken to do it, but in person this looks like a perfect application for anaerobic. YMMV

 

[D60]

Well this has been a funny one. I started refilling the transmission Saturday night and still had a healthy drip once I got 8 qts into it.

It took about 2 seconds to see it was coming from the pressure sensor on top right of the bellhousing. Scary version? It wasn't dripping noticeably from here during diag (but remember I never filled the transmissionmission to the correct level), so that tells you how low it was and/or was having trouble building appropriate pressure. The sensor was very crusted but I thought it had just been flung up by the axle.

As a sanity check I used soapy water on the sensor. Pushing air into the fluid side I was able to generate bubbles right at the arrow. Appears to be failed potting:

The sensor can be had as a PS695 which runs $130‐140 at O'Reilly. Even RA wants about $120. Beware: AutoZone attempts to sell their Duralast version for $285 retail, meaning they didn't get the memo that house brands are supposed to be less expensive

In truth the sensor was the bigger leak all along, but I need not feel bad about pulling the transmission because here was the oil pump cover leak, and note the nice puddle at the low point of bellhousing:

Now here's a screenshot from Subaru's own TSB, and if my example wasn't the definition of textbook failure I don't know what would be:

A moment for Sir-Rants-A-Lot: this is an example of why "sealed" transmissionmissions can be problematic. Even if you wanted to train the average user to check fluid level, it's not practical with no dipstick. And even if you knew it was low, there's no such thing as a quick top-off.

This lady is 60, heavy set and doesn't know much about mechanics. She can't get under a Subaru to just look for oil leaks. But she's quite sharp and could read a dipstick if I showed her how.

 

[D60]

Here's the new Standard sensor vs OEM. More crimping and less potting, although I'm sure there's still a sealant or epoxy crimped in there.

Here's the location as viewed from right fender:

Here's the connector which shoulda been a clue, but I just ain't that bright. I see now also one of the wire seals is backing out. ATF isn't particularly kind to some rubbers.

edit: a basic 1-1/16" chrome socket got me there....looks like that'd translate to 27mm if you have one. An impact socket may not have enough depth to accept the plug

 

[JRHAWK9]

When I resealed the pan on my Crosstrek, I used this stuff. So far, so good.

https://www.permatex.com/products/g...automatic-transmission-rtv-gasket-maker-3-oz/

 

[D60]

Subaru's TSB details a new lip seal they say should be installed. The TSB shows this but here's a shot of my own:

The TSB also stresses that gravity may stop working if you don't use their special seal driver 927890000. As best I can tell, it's been discontinued for some time. Be careful if you search the web for the tool. Presently one of the most promising looking results is a random site called "BuyTavo" which seems to definitely be a scam.

ANYWAY to install the new seal I just used my arbor press and a drop of 2.5" pipe that I faced on both ends to ensure it's square. The ID is large enough to clear the seal lip but small enough to catch the body of the seal. The OD is large enough that you simply cannot press the seal any further than flush:

The gear for the pump chain can slide off, so I zip tied it to prevent any headaches:

 

[D60]

Also not that it matters but the unit is heavy. My buddy and I tried to lift it off the transmission jack but we couldn't even get it to budge. I assume the fact that the front diff is integral is much of the reason for the weight.

I've moved around C6s, E4ODs, TH400s etc and they're not bad.....but the TR690 is stupid heavy. I assume a TR580 is similar. I wouldn't plan on bench pressing this unit in your driveway, and keep your mom on speed dial if you do