laegion

Is this a daily driver? Any other symptoms? Original engine? Has it been sitting for long periods of time? recent maintenance? other recent issues or parts replaced?

You're locking the center "diff" (which in most automatic subarus is a computer controlled multi-plate wet clutch in the tail of the transaxle [similar to a clutch in a motorcycle]) that distributes torque to the rear differential. When it's "locked" meaning the duty solenoid that locks the clutches is 100% locked with a switch (or automatically) then it essentially becomes a solid link between front and rear differentials like a traditional 4x4's transfer case (however with no gear reduction). When it's not locked the ECU controls the percentage of power transfer to the rear diff by changing the duty cycle of the clutch control solenoid, up to and including a full lock but will disengage so drive train components aren't damaged from tire scrubbing on dry surfaces. Most subaru's have open front and rear diffs. I've been looking into options for rear limited slip and I'm leaning toward looking for an STI rear diff with a torsen posi; although I haven't looked into it much yet and it's possible there is some reason that wouldn't work. Maybe someone else knows more about that aspect of things. It seems it would be easiest to swap in another intact subaru rear diff than swapping in a different carrier as that requires adjusting the diff gear's tolerances from what I understand. I've never done that part before.

When it's locked it's no different than any other locker. The mechanism is different but the effect is the same.

Well damn...that's really unfortunate. I was hoping I'd be able to rebuild the one in my '03 if it was bad.

I would assume there is a way to rebuild the VLSD rear diffs so that they function properly again?

From what I read, one of the studs doesn't line up with the ez30 gasket.

https://www.discountedsubaruparts.com/p/Subaru_2004_Legacy-25L-AT-4WD-Outback-Wagon/Exhaust-Pipe-to-Manifold-Gasket-Front-Exhaust-Pipe-to-Manifold-Gasket/49250540/44011AE050.html 3.0 is not listed in "what this fits" and alternatively no 4cyl listed on the "what this fits" for the ez30 gasket.

The gasket part numbers are not the same.

No. It's not the same. The exhaust gaskets for the manifold to pipe is not the same part as for the H6. The muffler is also different if I'm not mistaken.

I'm willing to bet you have enough clearance now....What will you be running for tires?

I'm not questioning the ground clearance numbers. You're just making a lot of assumptions about the strut mountings being at the exact same relative height on two completely different chassis models from two different decades.

How deep of snow are you planning to drive in? I have been in 2ft of snow in my '95 easily with just the outback struts and outback sized tires. I've only ever gotten stuck in packed, re-frozed snow. Which is why I carry my snow shovel in my roof basket during the winter.

I'm not sure your math is quite correct. You're assuming that the strut mounts are at the same height in the body compared to the undercarriage in each model and every year and I don't think that's correct or swapping to Forester struts would not be a thing if it gained less than an inch over an outback's normal clearance. It seems more likely that the 04+ Foresters have their strut mounts higher and therefore have taller struts than an impreza/outback/1stGenForester. Maybe someone wit measurements can clarify.

Probably don't want to hear this...but as much as you've lifted your car; it will make it difficult to regain that stability. I did not have this issue at all with my '95 with Outback struts.

Maybe adjustable end links would solve your difficulty? I'm pretty sure Primitive Racing sells some. Moog does also, I believe.

I dunno, if it is that big of a difference going to forester struts then it probably didn't have outback struts on it. From what I've read the '04 forester struts give about a 1-1.5" lift over the outback struts. Also, if it had outback struts in the rear and legacy struts in the front...I don't think it would be safe to drive. There's about 1.5" difference in height between the two. If that's the case I'd recommend going to outback struts if you don't want to be replacing axles and ball joints frequently. I have a '95 Legacy L on Outback struts and even with that much lift the axles and ball joints are kinda on the edge of a bad angle, and the brake lines are about at their limit. Also, you probably want to swap on some outback rear trailing arm brackets to make your rear wheels sit center in the wheel well. You could also get all of the subframe, etc. spacers from an outback to fix the angles. Also, if you want to level the rear you can make or purchase spacers and longer bolts for the top rear strut mounts. One can cut them from a high density plastic cutting board. I did 1/4" spacers in the rear of my '96 when I swapped in the Outback struts to help level the car, (mostly because the roof basket and trailer hitch receiver caused a little sag). However I'm sure a good quality kit is probably better.

It was low with outback struts? You're sure they were outback struts? It sounds like they were stock L struts.

3" would not be enough to fit 33" tires. You'll either need a solid axle swap or some serious wheel spacers and lift to manage that as well as some serious cutting. Not to mention the subaru gearing with tires that size and 160hp will make the thing a dog. Is there a specific reason you're wanting 33" tires on a Subaru?

Yup. I use an app called Dash Command. I don't know exactly what it takes to run but I've used it on all kinds of android phones. It should work on most phones; but there are lots of different apps and probably some that are specifically for diagnostics Dash Command is more geared toward being a digital dash.

Like Numbchux said. Some Subaru's started using OBDII in 1995. My '95 Legacy L with a 2.2 has OBDII although I'm not sure if it has all the same sensor readings as the cars '96 and after but it is useful. I was in a similar situation and wanted to get something with OBDII. I have a scan tool that will read a lot of the older OBD protocols but OBDII is just more convenient because the tools are cheap and ubiquitous. But I also have to agree with GD because OBDII isn't magic...it's just another protocol. If you're not good at diagnosis and you're most likely to pay a mechanic anyway then it's not really important compared to the condition of the car.

Seems unlikely as I just replaced the valve cover gaskets with brand new OEM gaskets.

I am not sure yet as I haven't gotten a stethoscope yet; but I believe it's a combination of things; possibly chain tensioners that sat for too long and are now not providing correct tension at idle; and/or 1 or more dirty injectors, and/or more weak ignition coils. The valves and chain may be making noise than necessary but the main issue I think that I was perceiving as extra noise is an intermittent miss; it doesn't throw a code but if I drive it too much like a grandpa or let it idle for more than 5 min it will have a slight miss until I do a medium (30% throttle) pull from a stop then it will run fairly smooth for a while (still not as smooth as I feel a flat 6 should be; but maybe the EZ30 isn't naturally as smooth as the EG33 is supposed to be?). Thankfully I've got 12 injectors and 12 coils to choose from; just need to do some testing.

The easiest thing to do is learn how your car loses traction (driving in snow is my favorite) as many have described here. Another thing that can help would be reducing the weight in the rear of the car and increasing the rear tire pressure by a few PSI that will help reduce oversteer in hard cornering. However I tend to stick to drifting in snow only. Dirt drifting/rally driving is reeeeally hard on the suspension/undercarriage/brakes/wheels and tires. Watch some videos on youtube of the mods they do to the Subarus they use at the drifting school out here in the PNW. I wouldn't want to put my Daily through that abuse with how much I pay to maintain it.

Very good point. I had a strange vibration and sound during sweeping turns a week ago and it turned out it was a wheel Les Schwab had worked on about a month ago and the lugnuts were backing out and barely finger tight. They gave me some nonsense about torquing Subaru Lugnuts to 90 lbs/ft. I dunno about others but I always roll my car a few feet and re-torque when I tighten wheels. Might be worth checking even if it seems too obvious...that's what I thought too and glad I checked!

My thought would be the tie-rod ends or the ball joint. From what you're describing it really sounds like a tie-rod end to me. Just because you can't register any movement with human strength doesn't mean it isn't loose; your car exerts far more force on those in turns than you could ever manage manually. The popping on bumps could be sway bar bushings or end-links. Also maybe check your tires for separated belts.