1. Can't say it's entirely normal or abnormal but the diff grinds are usually more apparent if your front wheels are on different mu surface than your rear wheels with the steering turned a lot.

2. Not normal at all.

3. Usually comes when ur fluid are expired, air in PS system or worse power steering pump is going. Some do get the whine when the fluid are hot and installing a power steering cooler is one of the common mods.

 

Do you have any maintenance records for the car? If so, when was the trans and diff fluid changed last? You may want to change them and see if it resolves your driveline binding. The best fluid for these cars is just plain old Subaru Extra-S. If you're racing it you should consider something more robust like motul.

buy it here: http://www.amazon.com/Subaru-75W90-Extra-S-Transmission-Fluid/dp/B007L6Q1EK

I just did mine on my '07, it took 6 quarts to do both the trans and rear diff.

Also, get the little pump! It will make life much easier!! You might need the Torx bit for the trans, Its a T-70.

Lastly, DO NOT drive the car with the diffs locked unless you're on a loose surface ie: dirt or snow.

Good luck!

 

Thanks guys. I do have an appointment Tuesday for my local dealer to take a look at the car. I'm going to spend some time with her Sunday, cleaning her up to my liking and messing around under the hood. Maybe I'll get a little further myself.

I read a lot on the DCCD but I never saw anything saying what speeds you should or should not engage in on. I did notice that if I locked it above 15-20mph it didn't pull my car to the right so much.. but now I know not to lock the diff on dry pavement ( wasn't aware of that before )

Also, I listened some more this morning to the car and I'm actually not sure if the whine while turning I'm hearing is the PS pump, or if its related to one of the other noises. I do know I don't get any noises other than a very slight hissing noise if I turn the wheels lock-to-lock while sitting still. Not sure what the small pump is, I'll have to look into that.

No maintenance records on the car as of now. Going to ask Subaru dealer if they can pull vehicle history like Ford does. I do know it was serviced 5 times at the dealer by the last owner, but that was basic stuff.

Planning on swapping the fluids, thought about the motul. My plan with the car is an Accessport V3, Cobb SF intake, and trying to find a subtle but grunty exhaust for the car. I like the SPT exhaust but I'm not sure how restrictive it is for tuning? This is a daily, and after it's sorted I want to make 300-350awhp, reliably. Don't want to do too much bc I don't really drag or anything unless someone happens to have an event near me.

 

I have an 06 but the drive line is relatively the same. I would check bushings when it comes to vibration. I can tell you when I changed out all the bushings and mounts in my car I noticed a very distinct vibration at 2000rpm. I figure its something the original liquid filled engine mounts soaked up. I have not noticed any issues from the vibration so I just class it as normal with stiff mounts. Same with the tranny. A hardened rear mount bushing will increase gear noise.

Second, as was said do not lock the diff on a high traction surface. The center diff allows the front and rear axles to rotate at different speeds during a turn. Locking the diff on say a dry tarmac road will cause drive line wind up which binds the system as the tires can't easily slip. This could result in damage. On 4WD trucks the result is usually a broken u-joint on the front axle. That or a broken half-shaft.

Third, I'm not sure if this is your problem or not, but there is a notorious o-ring on the p/s pump. It's located on the plastic nipple that is attached to the return line and is held in place by a small bolt. It's prone to deteriorate over time. This in turn allows a small amount of air into the system which causes a whine. I don't know if that's your problem, but I would start there.

 

Have the engine pitch stop and trans crossmember bushings been replaced with aftermarket? This will cause the exact whine you are describing, i.e. whine in 1st and 2nd, gone by 3rd.

Power steering hiss: the theory is that the PS systems in our car over heats the fluid, even with normal driving. Myself and others have installed a PS cooler + new fluid and the pssshhhh has vanished completely.

 

Per OP...... "Planning on swapping the fluids, thought about the motul. My plan with the car is an Accessport V3, Cobb SF intake, and trying to find a subtle but grunty exhaust for the car. I like the SPT exhaust but I'm not sure how restrictive it is for tuning? This is a daily, and after it's sorted I want to make 300-350awhp, reliably. Don't want to do too much bc I don't really drag or anything unless someone happens to have an event near me."

You don't need a CBE for tuning or whp, but a good DP with almost any cutback will work fine. Suggest getting an up pipe to aid spooling. You'll need pro-tune, upgraded fuel pump, EBCS and possibly larger injectors and headers if you want whp near 350.

 

You don't need a CBE for tuning or whp, but a good DP with almost any cutback will work fine. Suggest getting an up pipe to aid spooling. You'll need pro-tune, upgraded fuel pump, EBCS and possibly larger injectors and headers if you want whp near 350.

was that supposed to say a good DP with a catback? It's late.. I'm tired... just making sure I didn't miss anything..

And for the love of God, why can't I find a good write-up or halfway decent information on servicing the center diff on our cars? for that matter it seems like GR Sti information is scarce as well ( in comparison to GD ). Maybe my search skills suck... but I was on this forum from 7pm-11pm tonight.. so it's not like I don't try... it just seems as if I keep only finding the forums where people ask the same questions.. like 'what does DCCD do' ... lol.

I swear I'm gonna end up writing a book before I'm done with this car.

 

Thanks for the advice guys. I'll have to wait until Sunday to hopefully get under the car... it's raining.

The thing I thought was odd about the diff pull, was i was going in a straight line, engaged manual mode which was already set at full lock, and as soon as it locked in, it turned the wheel right towards the curb.
Again, not using full lock on pavement again nor have I driven around more than 2-300 feet with it on since I got the car. Usually leave it in Sport mode (SI-drive) and mostly cruise around.

I'm starting to wonder if the rattle is a heat shield or something... still definitely have gear noise. I'd like to do a full tune-up on the car and see what happens as well.

I did notice on the way home while in traffic, that as the noise starts to disappear, the vibration transfers from the front/center of the car to the back.. like it's sending it down the driveline.

I still need to do more research on the front, center, and rear diffs, what fluids are better for each, life expectancy, etc. Going to look into the FAQ's section.

If I don't find what I like, I'll probably do a full write-up as I learn information. Maybe I've missed it, but a GR write-up on all of this stuff would be awesome.. (I found a couple, but they are for the GD's)

I'll post a video of the noises as soon as I can with my Hero4 on my youtube channel and put a link in here. I'd like to keep this updated in detail so if others have the issues there is a well-documented place for them to find help.

 

If your steering is pointed straight, the car shouldn't pull to any direction even if it's on full lock. Either something is binding on one side or alignment issues or tramlining etc etc.

 

Ok guys, I got a video up on youtube of the car. It was quick and rough but I did what I could.

https://www.youtube.com/watch?v=ABphX4lapHQ

 

nothing?

Diff Lock issue resolved itself... dummy me freaked out and forgot I had a spare on.. haha! new tire, no problems.

Rear diff appears to be the 'diff klunk' everyone refers to... will be looking into klunk killer soon.

so only real issues left are the hesitation and slight misfire I'm getting at idle and under boost. Nothing aggressive, but I can feel it. Going to change the plugs and see what happens.

And the transmission rattle. This, I have no clue. maybe an input shaft bearing? maybe the vibration from the driveline is rattling a heat shield right at 2000rpm? Haven't had a chance to get under the car yet.

On a good note, I just received 6 quarts of Motylgear 75w-90 to replace my trans and diff fluids with

Basically trying to figure out if I want to fix everything with this car (not bad stuff I'm just really picky)
Or drive it for a year and set most of my parts off to the side and buy a 2011 Spark Silver with low miles and start there... Either way I end up switching parts... love the SSM color, like the heated seats and better suspension on the newer cars... and low miles never hurts.. (I'm at 84,000 right meow)

but I much prefer the dash trim colors and the charcoal suede on the 2008-09 cars... so I add heated seats to mine...( is that possible? ) and go through the car.. or I get a newer one and swap in an 08-09 interior...
First world problems right?

I'm rambling... but I just ordered a new right side door switch trim because the last owner's wife scratched the shit out of it with a wedding ring. Also ordered some other little bits that I just felt weren't clean enough inside.. as well as a paper copy of the service manual.