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Jerky 5-speed manual


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2003 OBW. 5 speed.

 

I did all the motor/trans mounts, and the diff mounts, which helped a bit, or at least made it different, I just got new control arms with preinstalled bushings, new rear oem bushings, and ball joints. car is a tick under 200k.

 

It still feels like a subaru, but the jerky slop is all but gone.

 

Also, Id like to mention that I was going to use group n rear bushings/mounts, until I realized that the outback bushings pickup point is lower than other subarus to correct for roll center, while they will fit, Id rather have stock bushings and not screw up my rc...

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With the control arms/bushings being a part of the suspension, I can't imagine this being the driveline slop culprit. That said, I do have a suspension issue in the front that makes a thudding sound like I'm shaking a box of rocks when I go over bumps at less than 30 MPH. That's probably what the control-arm bushings would fix.
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Is OBW Outback Wagon?

 

Can you better describe (or provide a pic or part number) for these bushings? I'm tired of chasing the problem and would like to at least be able to identify it next time I get the car on a lift.

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When you shift/coast etc the load pushes and pulls on the control arms longitudinally, my mushy old bushings were allowing excess movement which was pushing the drivetrain around, was like a wave sort of.. when I did the drivetrain mounts it seemed more under control, but same basic feeling, now its pretty much gone, as I said.

 

Im talking about the bushings that mount the front ca's to the front subframe, subaru calls the front lateral link bushings....

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  • 2 weeks later...

When I did an in gear roll test, my car has less slop than any car I can remember. Its not mechanical lash in the drivetrain, at least not in my case. Ive dealt with that before on other cars. This is an issue of mounting drivetrain components, and crappy engine response.

 

Your box of rocks is likely a ball joint, or even a loose fastener.

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Any thoughts on where this loose fastener might be? We've checked just about everything without any result. All mounts have been replaced. No bushing display any kind of measurable wear or looseness. Ball joints are fine. A friend's (tech) suggestion is to remap the computer or map it from a 2000 like my other GT to see if there is a change. Is this possible? Any reason a map from any 2000-2004 wouldn't work?
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  • 3 months later...

wow, 18 months on this thread, and now more like 21.

 

couple comments:

 

1) I can't speak for a 00-04 Legacy, but lots of built-in designed-in slop on a 05-09 OB. I wouldn't describe the issue I was trying to diagnose the same way as OP, but a lot of bushings each wearing a little could add up to a lot of lash. Next stop: google Subaru drivetrain lash.

 

2) no one mentioned rear diff lash. Jack up the rear, wheels off the ground, e-brake off. Crawl under, hold driveshaft with one hand (at different points to isolate movement), and rock one rear tire with other hand. I've seen considerable "lash" between the rear u-joint (isolating it out) and the wheel. Could be the rear diff pre-load....or wear resulting from that not being right for quite some time.

 

3) use same thought process to see if issue is in either/both rear axle CVJ's.

 

I'm not sure how unusual this is, but a rear diff with a lot of lash could result in a "jerkiness" associated with on-throttle/off-throttle transitions. And CVJ's are a known issue with any car that has them.

 

Just my 2 cents

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I guess the CV joint theory is as good as any other we've come up with here so far. And it makes sense because the rear CVs probably never get changed or serviced (at least mine have been there from the start), whereas the fronts wear out from the heavier demands on them, the boots rip and they get replaced. I wouldn't want to just start replacing CV joints hoping that it might fix the problem though.
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  • 3 weeks later...

A friend had this on his GT sedan 5MT, and mine was also still snatchy after a bunch of tries to fix, turns out there is a neutral switch on the transmission that wears out and makes the ECU think its in neutral/have sucky on/off throttle response and jerky tendencies.

 

Its about a $25 part, and was super easy to install, took maybe 15 minutes in the driveway.

 

Also, he was getting a CEL when coasting in 5th sometimes, P0519 an IAC malfunction, this has also stopped and is associated with the neutral switch.

 

Here are some links I read about it. Been a few days for both of us, and so far so good.

 

http://www.subaruforester.org/vbulletin/f89/neutral-switch-78655/

 

http://forums.nasioc.com/forums/showthread.php?t=1796446

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So I'm going to be getting my engine rebuilt in the next couple of months, and I see a lot of people mentioning group N mounts. Can someone link me to where I can purchase Group N engine, transmission and differential mounts? Having my engine rebuilt means I'd only be paying parts and not labour, so it makes it a bit less un-worth it.
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notaduc - I'll bite, it's cheap enough to give it a shot. I'll be ecstatic if this actually fixes the problem after all the other stuff I've tried

 

@itsGMS:

Rally Sport direct has them here, and subaru genuine parts should have them as well. Send an email to both places and see who's cheaper with shipping up to Canadaland

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If you do, Id like to hear if you see results.

 

After maybe 250 miles now its still far smoother, no CEL, better off idle torque, better mileage, its a little snatchy here and there but not anything as bad as it was. Time will tell.

 

I was ready to sell the car before this.

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I'm not getting the code.

 

The part is cheap, and it's easy to R/R, so it might be worth a shot. Also, a lazy IAC will make for a jerky ride in stop-and-go traffic. Does the engine dip below normal idle speed momentarily when you come to a sudden stop? In any case, it's easy to clean the IAC (and the entire intake at the same time) with Sea Foam. If you buy the aerosol can, you can remove the air filter and squirt it into the hole in the throttle body that leads to the IAC. I think the IAC, and probably the air assist solenoid valve get gummed up after a while from the engine having to breathe its own blow-by.

 

Best wishes,

Myles

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  • 1 month later...

A local race shop has taken this on as a personal mission. They just started three weeks on it. New engine mounts helped the symptom, but it is clearly a computer air/fuel issue and still feels nearly identical to drive.

 

They are chasing after the IACV system which is quite different than the one on my 2000 GT. In the early years, they were different from auto to manual transmission, but in the later years (2004, anyway), the manual used the same clunky system as the automatic.

 

They are trying to find out if a throttle body swap would work directly or not, and if so, if the computer would need anything reprogrammed. They are working with Subaru on it.

 

Thoughts? Has anyone else found a problem?

 

Which IACV is on the 2003 with the problem (posted above)?

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A local race shop has taken this on as a personal mission. They just started three weeks on it. New engine mounts helped the symptom, but it is clearly a computer air/fuel issue and still feels nearly identical to drive.

 

They are chasing after the IACV system which is quite different than the one on my 2000 GT. In the early years, they were different from auto to manual transmission, but in the later years (2004, anyway), the manual used the same clunky system as the automatic.

 

They are trying to find out if a throttle body swap would work directly or not, and if so, if the computer would need anything reprogrammed. They are working with Subaru on it.

 

Thoughts? Has anyone else found a problem?

 

Which IACV is on the 2003 with the problem (posted above)?

 

That seems like a reasonable hypothesis. It seems like my 2002 GT (EJ251) cuts the fuel abruptly when the throttle is closed, and the IAC doesn't react quickly enough. Driving this car smoothly, even after 12 years, has not become second nature. I'm always having to shift it very deliberately. Please share the speed shop's findings.

 

Best wishes,

Myles

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Selym, what does yours look like?

 

 

The one on my 5 speed 2000 GT looks like this:

http://www.partsgeek.com/assets/rep/full/1081673.jpg

The one on my 5 speed 2004 GT looks like this:

 

http://product-images.highwire.com/2183257/3254725.jpg

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Selym, what does yours look like?

 

 

The one on my 5 speed 2000 GT looks like this:

http://www.partsgeek.com/assets/rep/full/1081673.jpg

The one on my 5 speed 2004 GT looks like this:

 

http://product-images.highwire.com/2183257/3254725.jpg

 

There is no easy way to swap from one style to another. The top IACV is the older CA spec system that goes along with a 4 pin Front(A/F) O2 sensor. It has vacuum built in.

 

The bottom IACV is 6 pin and goes with an Air Assist Solenoid valve (you can find it on the front passenger side of the manifold with a purple connector) and the wideband O2 sensor.

 

If you have the old style you need to add a bunch of wires and hard parts to switch to the new style as well as a computer swap. Best way would be to clean out your original IACV or replace with new.

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yes...but that isn't the problem. The problem is the design of the new one which was made for AT. They used it on later model MT systems without much luck. My 2000 is glass smooth while the 2004 spills drinks with regularity. :)
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