Wayne Boncyk

I agree with grossgary. Try a full fluid flush (at least 4 complete drain and fills, with just enough driving in between to flush all the old stuff out from the nooks & crannies if all you're doing when you empty it is pulling the drain bolt on the bottom of the tranny pan). After that, then try driving slowly through a few figure 8s in a parking lot. If the bind doesn't noticeably decrease, then pulling the rear extension housing on the tranny is your next step. He's also right in saying that if you end up replacing all the parts in that extension housing with new, then you're probably better off just swapping the tranny. However, if your problem is only a sticky Duty C solenoid then for under $100 in parts (new solenoid and extension housing gasket) plus some new tranny fluid you will solve your problem. Its actually one of the easier repairs to do on a sube powertrain. Hardest part is breaking free the 11 (I think its 11) bolts that hold the extension onto the back of the tranny housing. And nipper will probably again complain (as he almost always does when I suggest this) but I'm a believer in synthetic AT fluid -- my 4eat runs MUCH smoother since I switched to synthetic.

Or, is this a MT only thing and did I just confues myself? It's been known to happen! :-\

Manarius, I don't get it. With the 4eat, turning on the Duty C solenoid 100% locks up the system in Front Wheel mode. That's why you can switch to FWD mode when a fuse is inserted in the FWD socket; you turn the Duty C solenoid ON full time when that fuse is there. It is only when the Duty C is OFF (or stuck) that the 50-50 front-rear coupling is constant. So, maybe what they really are doing is interrupting the control voltage to the Duty C solenoid with a switch that is opened when you want "full time" 50-50 split. I can see where that would work, but I can also see where that would throw AT codes and cause your AT Temp light to flash on startup -- not a good thing unless you know what's really going on there.

Wow, nipper! Although my opinion of timing chains isn't fundamentally changed (since I had one shred cam sprockets on an old Oldsmobile V8 back in the early 70's and the more I disassembled on that beast, the more I found broken, until I finally gave up and we towed it out to an empty field where it still does duty to this day as the neighborhood pellet gun target), these Fuji guys are impressive with their almost mystical approach to engineering. I'm sure that no American car mfr ever had a single engineer dedicate 2 YEARS to becoming one with his timing chain design!

Yup - although his earlier comment "...tossed a rod" probably should have given us a clue.

Chains may last longer than belts, but that doesn't mean you won't have a failure down the road -- and being lulled into a sense of false security by having a chain, you may be more likely to end up with a pile of loose valve stems, grooved cam lobes and stuff where your heads used to be, not to mention some interesting looking valve head impressions on the tops of your pistons. I don't know what chain design the sube 3.0 uses, but a lot of chain timed engines out there use sprockets with nylon teeth on the cams -- so instead of a belt breaking you end up with sprocket teeth shearing. I think I'm actually happier with a belt timed system. More of a hassle since you have to change them out periodically, but if you're good about following the maintenance guidelines, they're not any more prone to trouble than the chain designs.

They're hopin' to SELL that video??? For REAL money????

ARRGH! Now you're BOTH doin' it!! SSSHHHH!!!!!

OK. I can see where, if you can't do the work yourself, you might be inclined to do a swap rather than have the HG work done if you are convinced that HGs could be a recurring problem. But have there really been that many cases of repeated HG failure? In my experience (admittedly not a whole lot - I have one car with the 2.5 in it), once the replacement was done, the problem was solved.

Actually, I think that Subaru may, in the process of trying to fix the HG issues with early 2.5's, have given themselves even more headaches. From my reading of all the 2.5 HG issues both here on this forum and in other places, the early 2.5's had the coolant loop to cyliner failure that was fairly readily fixed by going to their newer HG design. It appears that in later 2.5's they "overengineered" the solution, and they gave themselves more HG failure modes in the process. Sometimes the easiest fixes are in fact the best. I guess I'd qualify my earlier comment to say that I would want a '96-'97 vintage 2.5, if it was about to be sold for scrap....

you beat me to it again, nipper! But, anyone else has a 2.5 that they want to get rid of....

Oh, I know. I was speaking a little tongue in cheek. However, while it is true that the 2.5 has had more than its share of HG issues, statistically it still isn't as bad as many other mfr's engines for general problems/issues. And anyone who would balk at HG replacement might, IMHO, also have a bit of a tough time with an engine swap. Personally, I'd rather pull the heads a few times than swap out a whole engine once. I've done both at one time or another, (although not on the Outback -- yet) and doing the heads was a quicker job. (in reply to grossgary, not nipper!)

Hey, nipper! Don't give away the store, man!! The longer all these guys believe the rumor and gossip about 2.5's the cheaper they'll be when I get around to replacing mine -- but that won't be for quite some time. 220K miles, still going strong. Sure I did a HG replacement way back in this engine's storied past, but hey, Subie ownership ain't for wimps! :cool:

Like I said earlier, jerking because the wheels make/break traction in an unpredictable manner when you're riding over top of a thin layer of water. That's my guess. You feel it differently in an AWD vehicle than in 2WDs.

O2 and Knock sensors are both pretty easy to change if you've got some mechanical experience, the tools needed, and some time. The O2 sensors will be more difficult than the Knock sensor, since they're in the path of hot exhaust gases and that causes them to get stuck in their flanges. Expect to spend some time waiting for a penetrating oil (like PB Blaster or similar) to help to free them up. You should have 2 O2 sensors on that vehicle, right? One at the front of the Cat, and one at the Cat output to the exhaust pipe. Sounds to me that you may need more than just sensors -- just because the OBD codes tell you that something isn't right with them doesn't mean that the sensor has necessarily failed. From what you're describing, I would guess that your timing is off a bit, too. Perhaps the timing belt has jumped a tooth. Just a guess -- but unless you do a little more detective work, all we can do is guess.

Manarius is right -- and at higher speeds, I've often felt a little "jerkiness" on snow and ice in my Sube as well. If all 4 wheels are slipping, no amount of AWD will help. What you were probably experiencing (this is a guess -- but it seems to make sense) is that you were floating on all 4 wheels for a good portion of that time when the rain was heavy, but occasionally one pair or the other would catch hold of enough pavement to grab a bit. happens to me on ice all the time -- although I'm not usually cruising at 60mph when it happens!

Didn't know about that. Sorry for the bum advice!

Mike - What an EPIC saga! Sorry I've been away from the forum for a few days, or I might have jumped in earlier. Not that I'd have had anything to add to the incredibly detailed advice that you got from everyone else here! I'm just dropping in now to say Kudos to all the guys who helped you out. This has been an incredibly enjoyable read, mostly because it reminded me of some of the longer threads I've been a party to over the past few years in this forum. As my kids would say, you guys all rock! There is absolutely no better source of information on Subes anywhere else in the world -- and it is all the better for being from guys who actually work on their own machines -- the ratio of real useful info to BS is extremely high on this board, and it is wonderful to see that there are so many folks out there who value their machines so highly that they are willing to share their decades of combined knowledge with the rest of Sube owners around the world. Nice job, gentlemen!

I can give you one good data point for aftermarket O2 sensors. I have bosch generics in both the front and rear spots on my 96 OBW, and they have been working fine for 9+ months now. Given the physics/chemistry of how they work, these aftermarket jobbies might wear out faster, but they'll provide exactly the same voltage variation while there's still enough reactant left in the probe for them to work... so cheaper is OK, if you are willing to trade lower cost for the possibility that you might have to change them out sooner. Again, the Bosch generics work just fine in both positions, at least for my 2.5L exhaust. Passed Colorado state emissions inspectin with flying colors, too -- better numbers than I had on the last test I had done, in California a couple of years back....

I can confirm that the wet sanding approach, followed by a clear coat, works and lasts fairly long (at least 6-12 months, which is how long I've been driving since I did it on my '96 OBW). The trick is to clear coat. Without a protective layer on the plastic, since it does still have some microabrasion remaining after the sanding, it will fog faster (as mine did the first time I tried the sandpaper technique). Also make sure that you finish with the highest grade of paper that you have the patience to do -- IMHO, 4000 is not too fine! The smoother you can leave that outer surface prior to coating it, the longer your polish efforts will last.

Unfortunately the failure scenario that you describe can happen in these Chrysler minivans regardless of tire size differences. I know, because it happened to us, and I know we had a matched set of 4 tires. Turns out that as nipper says, the clutches in this design are prone to failure, especially in earlier model years of the AWD system. We had a 1994 plymouth grand voyager with this system, we had a clutch failure that resulted in full coupling to the rear wheels (as full as the viscous coupler would provide anyway), and we ended up with the vibration and burning oil smell that you described. When I took our van to the dealer, they saw the problem and after conferring with Chrysler they ended up eating the cost of completely replacing the rear end and the coupler. Our front diff was supposedly "fine," but IMHO the van never drove as smoothly as before the failure. Our failure happened at 64K miles, 14,000 past our drivetrain warranty, but I guess they didn't want the hassle of yet another dissatisfied customer so they didn't pass the repair cost on to us. That's the nicest thing that an American car mfr. has ever done for me, and it was the last time that we were treated so well. Later on in the van's life all the paint began to flake off and we were eventually left with a vehicle that was 40% paint, 60% primer. Chrysler steadfastly refused to own up to the fact that they used a defective primer during those years, and although thousands of people tried to recover at least partial cost of repainting the vehicles, I don't know of any who were successful. We certainly were not. I am suspicious of Chrysler to this day because of that episode, and despite their best attempts to get us to buy a new minivan in the ensuing years, I haven't ever given it a serious thought. Good luck with your case. Although I can't believe that your tire caused your problem, it may have contributed to the final failure. I'm sure that Chrysler would rather provide you with an official warning statement about differing tire dimensions than own up to the fact that poor design and a catastrophic failure mode led to your situation!

Michelle, the colorant may not show anything definitive. Phase 1 engine HGs usually fail such that the coolant jacket leaks into a combustion chamber. So during high compression (like right after ignition in the cylinder), hot exhaust gas is pushed into the coolant loop. That's what causes coolant loss (from local boil-off) and overheating. The phase II engine HGs ususally blow such that a channel opens up between the coolant loop and the outside edge of the head. Only in that case will you see a colorant stain at the place where the head meets the block. As someone else noted here, the Subaru Goo fix only works on this phase II failure. Nothing except HG replacement will work for the phase I repair. What's worse is that the problem usually only shows up during periods of high mechaincal load on the engine, so the usual checks (like compression tests) won't tell you which side has failed -- you usually are better off if you get both HGs replaced. Your guess at around $1000 for the job is on the low side of the estimates that I got to do the job for my '96 OBW (which ranged from around $1200 to over $2000), so I ended up spending a few weekends doing it myself.

Actually, I was a little unclear. The Duty Solenoid and that manifold plate together comprise a switch. It changes the relative pressure of AT fluid on one end of the clutch plate assembly, which causes the plates to couple power to the rear driveshaft when they're engaged by that switch. Note to those of you who are trying this at home -- make sure that you either change out that manifold plate (and its gaskets) or that you are sure that there are no obstructions in the channels cut into the plate, or all your hard work getting to and swapping out the Duty Solenoid will be for nothing.

Hey, I'm all for this kind of experimentation to see if these ideas really work. If you can demonstrate more than a few % difference in the scored heads vs. non-scored heads, then I'll be interested in trying it myself. More power to ya!

There's more on this forum, too. Search on posts by me from about this time last year, and earlier. You'll find that I experienced the same symptoms, and did exactly the same thing you have done thus far (i.e. the FWD fuse). I ran for a very long time before getting around to disassembling the rear extension housing on my AT, but the bottom line is that you can do the work yourself, replacing the Duty Cycle C solenoid, with the manifold switch under it, takes about 5 mins once you have the extension housing removed. If you find either sticky clutch plates (where two or more don't move freely with respect to each other) or if you find scoring inside the extension housing (since until 1997 they didn't use a bearing on the extension housing and the output shaft could wear the housing enough so that the clutch plates would start rubbing on the inside of the housing itself), then you'll have to replace those parts, too. Nevertheless, if you're at all mechanically adept you can do this all yourself for probably around $100-$250 in parts (some used) vs. the $800-$1100 you'd have to shell out if you went to a dealer to have the work done.