Charlie529 Posted October 30, 2021 Share Posted October 30, 2021 First time Subaru owner. I recent acquired a 2012 legacy 2.5gt 6mt. It quickly began showing signs of what *seems* like a bad viscous coupler. I've watched the repair vid, but it's on a 5mt not the 6mt. My question is whether or not a viscous coupler repair on the 6mt turbo will be significantly different than on the 5mt? Has anyone here done a viscous coupler swap on the 2.5gt 6mt? I'm a bit of a noob trying to learn my way, so please, be kind if I've said something stupid here. Thanks :) Link to comment Share on other sites More sharing options...
idosubaru Posted October 31, 2021 Share Posted October 31, 2021 All 2010-2021 6 speed trans center diffs are the same part number. The exploded view diagram makes it look basically like the same process. Pull extension housing and juggle a few extra parts and shafts. (for reference only): https://parts.boardmansubaru.com/a/Subaru_2012_Legacy-25L-TURBO-6MT-4WD-GT-Limited-Sedan/_80160_6027583/MT--TRANSFER--EXTENSION-EXTENSION/B14-121-02.html I’d get the factory FSM even if you knew exactly how to do it so you can see all the parts, steps, torque values in sequence. Not hard to find for free. With that it might be obvious if it’s similar to the 4 cylinder models. Link to comment Share on other sites More sharing options...
Charlie529 Posted October 31, 2021 Author Share Posted October 31, 2021 Thank you idosubaru, that's exactly what I needed to know. Link to comment Share on other sites More sharing options...
Charlie529 Posted November 1, 2021 Author Share Posted November 1, 2021 (edited) On 10/31/2021 at 4:11 AM, idosubaru said: All 2010-2021 6 speed trans center diffs are the same part number. The exploded view diagram makes it look basically like the same process. Pull extension housing and juggle a few extra parts and shafts. Is there any way to isolate whether the issue is with the viscous coupler / center diff vs the front differential? Car shows classic signs of center diff failure, but mechanic says he "feels it all in the front, so it must be front diff" and therefore needs a new transmission. I can't afford to throw money at this and a tranny is out of the question. Car has no symptoms cold, but locked 4wd when warm, noticeable when parking, and worse after highway. Edited November 2, 2021 by Charlie529 1 Link to comment Share on other sites More sharing options...
idosubaru Posted November 2, 2021 Share Posted November 2, 2021 3 hours ago, Charlie529 said: Is there any way to isolate whether the issue is with the viscous coupler / center diff vs the front differential? Car shows classic signs of center diff failure, but mechanic says he "feels it all in the front, so it must be front diff" and therefore needs a new transmission. I can't afford to throw money at this and a tranny is out of the question. Car has symptoms cold, but locked 4wd when warm, noticeable when parking, and worse after highway. Yes - your description verifies it's the VC. As you said classic symptoms. Good description and notes. locked 4WD, parking, when warm, after highway...all are just what you said, classic. Well done diagnosing! Also front differentials in Subaru's...I hate to say "never" but, yeah, never have "only binding" as a symptom. They don't even really have binding as a symptom. Or - if they have binding they would be so bad you wouldn't be asking here. nearly undrivable or you wouldn't want to drive it. it would also have noise, grinding, vibrations, and awful shifting and drivability while driving straight as the driveshaft is walking back and forth in the case. Not just binding. The small percentage of Subaru's that are MT's make it likely he's never seen a VC failure in a Subaru. Many mechanics aren't overly familiar with Subaru transmission failures. Even if they see a lot of Subaru's it's often interspersed with other makes/models and failures, or few trans issues, they don't get an overview of common failure points and what does and doesn't happen with Subaru specific parts. Link to comment Share on other sites More sharing options...
Charlie529 Posted November 2, 2021 Author Share Posted November 2, 2021 13 minutes ago, idosubaru said: Fantastic! Thank you so much for your clear response. Feeling much more confident in going after replacing the center diff. Cheers! Link to comment Share on other sites More sharing options...
idosubaru Posted November 2, 2021 Share Posted November 2, 2021 4 minutes ago, Charlie529 said: Fantastic! Thank you so much for your clear response. Feeling much more confident in going after replacing the center diff. Cheers! You're welcome. I'm not saying base everything on what I've said, double and triple check and push me. but you're done your work and what you've relayed sounds almost definitiive. Link to comment Share on other sites More sharing options...
Charlie529 Posted November 2, 2021 Author Share Posted November 2, 2021 1 minute ago, idosubaru said: You're welcome. I'm not saying base everything on what I've said, double and triple check and push me. but you're done your work and what you've relayed sounds almost definitiive. Yes. It seems pretty straightforward being classic symptoms, so just needed some confirmation that I'm not missing something with the front differential. I'll look for a mechanic who has some more Subaru specific knowledge in the future or perhaps even for this repair. Though it seems a relatively doable job for someone like myself, I may chunk out the cash for peace of mind with someone who's done it before. I'll update here once the work is complete and I can confirm the fix. Link to comment Share on other sites More sharing options...
idosubaru Posted November 2, 2021 Share Posted November 2, 2021 List that VC for sale for someone who wants to convert their Subaru to RWD. Lol. A friend converted one to RWD that way. Link to comment Share on other sites More sharing options...
idosubaru Posted November 2, 2021 Share Posted November 2, 2021 18 hours ago, Charlie529 said: but mechanic says he "feels it all in the front, so it must be front I should ask - is this a high volume Subaru place, few Subarus or somewhere leaning one of those directions? I don’t want to go against the recommendation of a trained pro who does this every day and actually saw the car. I haven’t seen it, am untrained, and don’t do this every day! Link to comment Share on other sites More sharing options...
Charlie529 Posted November 2, 2021 Author Share Posted November 2, 2021 They are a general shop that is supposed to have decent experience with Subarus. I wouldn't call them a high volume Subaru shop, and I don't think he's done a VC, but I did expect a little more knowledge than what I got. He definitely doesn't understand how a viscous coupler actually works. When I questioned whether a front diff failure would have the exact symptoms of center diff VC issues without any other symptoms, he told me that the front diff has a lsd also that can result in the same symptoms - which doesn't seem accurate given the responses I've gotten from others while trying to diagnose. I really wanted the recommendation of a trained pro with eyes on the car, but was disappointed with what felt like a lack of knowledge. He also could not tell me how to isolate front vs center, I had to suggest removing the driveshaft as an option, but of course they want to charge $220 to do it. Being that it's classic center diff symptoms without any other issues, I'm inclined to trust my gut and the insights and experiences of others on here and just go ahead and replace it. I'll probably have it done at the Subaru stealership, since they should absolutely have the experience with the AWD system and know what other nuances to look for. Super appreciative for your thoughts and insights. Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted November 3, 2021 Share Posted November 3, 2021 Blackstone labs may be able to confirm silicone oil or wet clutch material in a fluid sample. But I think most of us would be confident with the cold vs warm change in behavior. Link to comment Share on other sites More sharing options...
idosubaru Posted November 3, 2021 Share Posted November 3, 2021 (edited) On 11/2/2021 at 1:40 PM, Charlie529 said: They are a general shop that is supposed to have decent experience with Subarus. I wouldn't call them a high volume Subaru shop, and I don't think he's done a VC, but I did expect a little more knowledge than what I got. He definitely doesn't understand how a viscous coupler actually works. When I questioned whether a front diff failure would have the exact symptoms of center diff VC issues without any other symptoms, he told me that the front diff has a lsd also that can result in the same symptoms - which doesn't seem accurate given the responses I've gotten from others while trying to diagnose. I really wanted the recommendation of a trained pro with eyes on the car, but was disappointed with what felt like a lack of knowledge. He also could not tell me how to isolate front vs center, I had to suggest removing the driveshaft as an option, but of course they want to charge $220 to do it. Being that it's classic center diff symptoms without any other issues, I'm inclined to trust my gut and the insights and experiences of others on here and just go ahead and replace it. I'll probably have it done at the Subaru stealership, since they should absolutely have the experience with the AWD system and know what other nuances to look for. Super appreciative for your thoughts and insights. Yep, guessing rather than not diagnosing, and not familiar with subarus. I could be wrong that it’s the center diff…but I’m not. Haha. Dealer is a great option, another good call on your part. They’ve got this job down, probably have the part and gasket in stock, will use the correct fluid, there isn’t much else job-specific to go wrong or get uncharged for on this job (still might upsell a brake fluid change or something else!), cost will be reasonable (high end but reasonable) and they will know it’s the VLSD as well so that’s a nice triple check (you - usmb - dealership) before going through with it. I’m generally picky about when and how to use a dealer and this is the perfect job and situation to let a dealership handle. Edited November 3, 2021 by idosubaru 1 Link to comment Share on other sites More sharing options...
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