Ok, so I just changed the transmission (and center diff. since it shares the fluid with tarnny) fluid on my 2005 WRX STi this weekend (car has 55k miles and I am second owner) and now I have steering wheel shudder at very slow speeds when turning the wheel.

 

 I can feel the shudder transferring into the steering wheel as you turn the wheel just off center, but most noticably at very slow speeds. I swear I don't remember this happening before changing the fluid, could I have intoruced a problem during this mundane fluid change?

 

 I extra-S (4.1 qts) from Fred Beans and followed the instructions on the on-line manual http://ken-gilbert.com/wrx/STi_Manual/

 

Any ideas? Could I have introduced too much or not enough air into the system to cause this? Any help is GREATLY appreciated!

 

What happens if you put the center diff in manual mode and set it to the most open setting? This might help point the issue to the center or front diff.

 

Also, 05 WRX Sti should be a 6spd, which the PDF in the attached link says takes 4.3 US qts for the transmission alone.

I tried setting the center diff to manual and changed the settings from 100% front stepping it thru 100% at each increment and didn't notice any difference. Yes, myu car is the STi and it has the 6 speed manual transmission. Do you think there is any chance the Subaru Extra-S fluid from Fred Beans isn't "correct"?

No, that's the right fluid as far as I know. It's GL-5 and 75W90 which is what the manual calls for. I was just concerned that at 4.1qts it might be a little low. Have you checked the level again since changing it and driving it?

I checked again when I got home last night and ii is PERFECTLY between the L and H.

Have you checked the power steering fluid level?

 

Sometimes this is caused by bad bushings on the steering rack. Did you happen to notice if the steering rack was covered in oil while you were under it?

The underneath of the car is VERY clean. It is very noticable since it spent all it's years (until I bought it this Spring) in the south. The steering rack was dry as well.

fluid changes are benign, you'd have to be really bad or unlucky for this to be fluid change related.

you just emptied it then refilled it, right?  can't get much simpler than that.

and you already checked the level, ensuring no loss of fluid, etc.

sounds good.

 

i'd guess after the fluid change you were more perceptive and picked up a pre-existing issue.

fluid changes are benign, you'd have to be really bad or unlucky for this to be fluid change related.

you just emptied it then refilled it, right?  can't get much simpler than that.

and you already checked the level, ensuring no loss of fluid, etc.

sounds good.

 

i'd guess after the fluid change you were more perceptive and picked up a pre-existing issue.

 

 Yes, I did simply drain and refill as you said. I have also verified that indeed the level is exactly between the L and H, so the level is not the issue. I am starting to believe it may have been due to me jacking the car up an putting it on 4 jacks stands may have stresssed a component (knuckle.wheel bearing,...) that was going to fail later, but is now happening sooner. I have resigned myself to letting a reputable local shop put it on the rack and "shake it down" to find the cuplrit. I will report the findings after tomorrows "shake down"

Peace

Try rotating your front wheels to back to eliminate a tire problem?

 Yes, I did simply drain and refill as you said. I have also verified that indeed the level is exactly between the L and H, so the level is not the issue. I am starting to believe it may have been due to me jacking the car up an putting it on 4 jacks stands may have stresssed a component (knuckle.wheel bearing,...) that was going to fail later, but is now happening sooner. I have resigned myself to letting a reputable local shop put it on the rack and "shake it down" to find the cuplrit. I will report the findings after tomorrows "shake down"

Peace

 

Where did you put the jack stands in the rear?

 

Many years ago a made the mistake of putting the rear jack stands on the plates that the rear diff carrier bolt to and I belt the plate up. This caused the plate to rub against the carrier during the right loading.

Where did you put the jack stands in the rear?

 

Many years ago a made the mistake of putting the rear jack stands on the plates that the rear diff carrier bolt to and I belt the plate up. This caused the plate to rub against the carrier during the right loading.

 I placed all four jack stands on the 4 corners of the pinch welds (normal jacking points) with a block of wood between the weld and stand

Well, I decided to take the STi to a local shop since my problem had me stumped and concerned. They recommended flushing and replacing the power steering fluid which fixed the problem! What a relief since I was thinking it could have been something a lot more involved and expensive. Thanks for everyones input!

Peace,

Joe

Joe, it isn't uncommon for the power steering pump to fail internally on this year of STi. I had a customer with a similar issue and just days after I replaced the fluid and it went away, he came back with a pump that had munched itself. Just be aware that a new pump from the dealer is upwards of $500

Joe, it isn't uncommon for the power steering pump to fail internally on this year of STi. I had a customer with a similar issue and just days after I replaced the fluid and it went away, he came back with a pump that had munched itself. Just be aware that a new pump from the dealer is upwards of $500

 Caboobaroo,

 

 Thanks for the heads-up. So you say this might not be "the fix"? How soon after the fluid change did the pump crash and burn? Were the symptoms the same as in the beginning or more catastrophic? If the pump does fail, is it straightforward to fix yourself and where would you recommend ordering the part from?

 

 Lots of questions:)

 

Thanks a lot!!

Edited November 18, 201312 yr by createaneutron

I believe it was within a couple weeks but exactly, I can't quite remember. It started with a shuddering at idle while sitting still, car had sub 100k miles. Fluid was a bit burnt and the customer asked if we could change it so I flushed it and the issue went away. Within two weeks it was back at the shop with a pump that failed internally and was full of metal shavings when I removed it.

 

Just make sure that if it does put metal into the system that it is flushed before the new pump is installed. Should be a matter of turning the wheels back and forth with the lines disconnected from the pump. It makes it easier with the wheels off the ground when doing it. I usually use a cut down oil quart container to catch the fluid coming out.

 

I believe the only place to get a new replacement pump is the dealer, or find a used one. If you're patient, it can be an afternoon job to replace it, for me, about an hour.

Edited November 19, 201312 yr by Caboobaroo

I believe it was within a couple weeks but exactly, I can't quite remember. It started with a shuddering at idle while sitting still, car had sub 100k miles. Fluid was a bit burnt and the customer asked if we could change it so I flushed it and the issue went away. Within two weeks it was back at the shop with a pump that failed internally and was full of metal shavings when I removed it.

 

Just make sure that if it does put metal into the system that it is flushed before the new pump is installed. Should be a matter of turning the wheels back and forth with the lines disconnected from the pump. It makes it easier with the wheels off the ground when doing it. I usually use a cut down oil quart container to catch the fluid coming out.

 

I believe the only place to get a new replacement pump is the dealer, or find a used one. If you're patient, it can be an afternoon job to replace it, for me, about an hour.

Well, it was about two weeks to the day when after I had the Power Steering system flushed and the slow speed wheel shudder disappeared, but then it came back! I then read on NAISOC about the "O"-ring failures that mimicked a bad PS pump. I decided to give that fix a try and the slow speed shudder disappeared! This fix was about $5, much better than replacing the PS pump!