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Jerky 5-speed manual


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Looking forward to hearing your results, rockhammer. The jerky performance is not normal. I drove a friend's 2006 Legacy, and it did not do this. I also don't remember my car doing it when I got it at 20,000 miles. It just crept in little by little over time. I never have replaced my clutch though, so it's possible that is a contributing factor.
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hey guys im not sure if this is teh same problem but i test drove a 2005 gt wagon that im lookinga t buying, adn the entire shifter tended to shift around a bit, is this normal? in my lancer the shifter is on a housign tahts bolted to the car and uses cables to shift so it doesnt move at all, is the legacy different does the shifter bolt to the tranny so it moves a bit?
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Unfortunately, (I'm pretty sure) you can't replace just the u-joints on these cars. You have to replace the entire driveshaft with embedded u-joints. Let us know if you do this and it helps, however.

 

Kind of thread digging, but someone else just posted here today.

 

Easy to remove/refit complete driveshaft. 12mm and 17mm wrench if I remember correctly. Just did one in the company parking lot... :eek:

 

The drive shaft can be split in the middle and paired with another (breaker's yard) part. I am told that the front section is transmission dependant and the rear part is model dependant.

 

The support bearing bracket (afixed to the front section) may also model dependant, check height. This can be removed from shaft if you have a puller.

 

I've seen postings around the net saying that you can replace the "staked in" U-Joints but this might not be cost-practical.

 

New shaft is $600+, I got a breaker one for $160.

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Looking forward to hearing your results, rockhammer. The jerky performance is not normal. I drove a friend's 2006 Legacy, and it did not do this. I also don't remember my car doing it when I got it at 20,000 miles. It just crept in little by little over time. I never have replaced my clutch though, so it's possible that is a contributing factor.

 

Unfortunately replacing my clutch didn't fix the jerking so I'm back to square one with this. The good news is that I needed a new clutch anyways so it wasn't a waste of money.

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Not what I wanted to hear, rock hammer, but thanks for the update. I'll be doing my clutch soon too, I suspect. 160k miles on it now. Someone else in this thread recently mentioned the carrier bearings being the culprit. I'm still inclined to believe them.
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  • 3 weeks later...

I'm really happy with my new clutch; shouldn't have waited so long. I still am nagged by jerking while coasting and going off throttle so I have been doing more digging. I haven't found any info on this problem by looking through our LGT forum. However, this does appear to be a problem that is discussed a lot in WRX/impreza/general subaru forums. Do a google search for "subaru drivetrain lash" and you will come up with a whole host of threads on various forums. Most threads lead to replacing transmission mounts and various bushings that hold the drive line in place. I'm going to try this before I drop the driveshaft and buy a new one (feels solid, no vibrations at any speed and doesn't rotate or pitch when I push it around by hand). I installed a Subaru group N pitch stopper ( http://www.rallysportdirect.com/STI-Group-N-Pitch-Stop-Mount-Subaru-Models-inc-2002-2011-WRX-STI )on Saturday before a 250 mile drive and I have noticed a small but not insignificant improvement in jerking when going on/off of the throttle.

 

I chose to do the pitch stopper first because it was super easy to install and could give me some idea if I was on the right track with minimal cost and work to install. The stock one that was installed was very lose in its brackets (bolts were 1/4 turn past hand tight), so I may have been able to get away with just tightening the bolts to the correct torque. I had the new part so I decided to throw it on anyways. After getting it in and putting my airbox back on here were my thoughts: jerking or driveline lash is somewhat diminished when going on/off throttle, moderate increase in vibration and noise when starting engine, very small increase in gear whine in 1st, 2nd and reverse gears, small increase in engine noise while coasting off throttle at low speeds, moderate increase while engine breaking at any speed. All of this noise is coming through the firewall (where the upper part of the mount attaches).

 

My conclusion is that this modification was easy to do but contributed little to fixing my issue. That said, it did help a little, but at the expense of a small increase in noise. My next step is to install Whiteline rear differential bushing inserts http://www.rallysportdirect.com/Whiteline-Rear-Diff-Positive-Power-Kit-Inserts-Subaru-Models-inc-2008-2011-WRX-STI which I ordered at the same time as my pitch stopper. My diff bushings are very worn (noticed this while trying to jack my car using the diff) and these pieces slide right into where the differential mounts onto the rear subframe. I can move my differential up and down almost 2 inches with my hands (bench press style) while I am under it as well as forwards and back (small amount of leverage with a pry bar) so I suspect these bushings will also help firm up drive train movement. I have had a lot of trouble getting the two bolts off, they are very rusted on and there isn't a lot of clearance to get any tools in there between the subframe and the spare tire well! I'll post my findings tomorrow after I take another stab at it. My next plan of action after I see how that works out (and I have another payday) I want to try to replace my transmission mount too. Anyways, hope this helps everyone.

[url=http://www.rallysportdirect.com/STI-Group-N-Pitch-Stop-Mount-Subaru-Models-inc-2002-2011-WRX-STI][/url]

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Nice info man. Checked some of the other forums like you said and found a bunch of similar problems. I haven't been under my car in awhile since winter but my diff mounts will be the first thing i check. I don't know why they never crossed my mind. Checked everything but those. Hopefully you find good results.
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Has anyone related the drivetrain slop with irregular clutch engagement? I know my clutch is junk but am curious if the jerking, which has gotten a lot worse, is contributing to the clutch wear.
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i would check the spark plugs...this can also be your timing, make sure all your pulleys and belts are in good shape.

Has anyone tried these suggestions? Any improvement? I am sorry for my previous post. Just reread it and realized it had nothing to do with your problem. I think I just have a shitty clutch.

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  • 5 weeks later...
No tranny fluid/dipstick on the manual. Its uses the diff. fluid for the gearbox

 

While this is true they use the same fluid there is still a small dipstick on the passenger side of the tranny. Have to remove part of your intake to find it and reach pretty far down to get it. Mine was covered in dirt and gunk and had a hard time finding it. It is bright yellow again now though.

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Okay guys I honestly don't think the Clutch has anything to do with this problem. My last car (volvo 240) had this EXACT same problem and it turned out the bushings that support the Rear Differential were blown.

 

Although there's a possibility that it's not the problem for this car, the Rear Bushings would be the FIRST thing I would check.

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Okay guys I honestly don't think the Clutch has anything too do with this problem. My last car (volvo 240) had this EXACT same problem and it turned out the bushings that support the Rear Differential were blown.

 

Although there's a possibility that it's not the problem for this car, the Rear Bushings would be the FIRST thing I would check.

 

I wish it was as simple as a diff bushing. First thing i did was check motor/tranny mounts and drivetrain bushings. Also idk how mounts would affect clutch engagement.

My thought is a warped flywheel. They can mimic bad motor mounts and cause some screwy clutch engagement.

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I wish it was as simple as a diff bushing. First thing i did was check motor/tranny mounts and drivetrain bushings. Also idk how mounts would affect clutch engagement.

My thought is a warped flywheel. They can mimic bad motor mounts and cause some screwy clutch engagement.

 

The thread describes a Jerky 5-Speed Manual and doesn't state problems with the Clutch Engagement.

 

Did you just check the driveline bushings or did you actually replace them? Visual inspections of bushings can very well be misleading to how they perform under load.

 

- Jake

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oop i guess i just added that bit, thought i saw it somewhere earlier in the thread. I get my forums mixed up. Anywho... i didn't replace them. i really dont want to throw parts at my car until i know for sure. I used a prybar to check for any abnormal movement. I didn't see or feel anything that would make me thing they're bad. IDK Im at a wall with what else it could be. :confused:
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oop i guess i just added that bit, thought i saw it somewhere earlier in the thread. I get my forums mixed up. Anywho... i didn't replace them. i really dont want to throw parts at my car until i know for sure. I used a prybar to check for any abnormal movement. I didn't see or feel anything that would make me thing they're bad. IDK Im at a wall with what else it could be. :confused:

 

It's a very confusing problem, that's for sure. I also see your logic in not throwing money into it until you know the problem for sure. It may not be a bad idea to borrow someone's GoPro camera and attach it underneath the car to go for a drive. You can then blip the throttle and find out what's moving so much. I may even do this.

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  • 1 month later...

This is one of the best threads on this topic, but since I own a 4th gen I posted here:

 

http://legacygt.com/forums/showthread.php/driveline-elasticity-209788.html?p=4479394#post4479394

 

It's a very confusing problem, that's for sure. I also see your logic in not throwing money into it until you know the problem for sure. It may not be a bad idea to borrow someone's GoPro camera and attach it underneath the car to go for a drive. You can then blip the throttle and find out what's moving so much. I may even do this.

 

Thanks for the idea Jacobpockros!

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I think that between these posts and the one above, we may have found the culprit: the transmission mount. See this part and the related comments here:

 

http://www.rallysportdirect.com/STI-Transmission-Mount-Subaru-5MT-Models-inc-2002-2011-WRX

 

Then we just need somebody to give it a try and share the results. I'll probably do it sometime this summer. And I don't think it would necessarily need to be this upgraded STI mount; even a new stock mount seems as if it would bring back the original specs for driveline slop tolerance. Also, the part is available cheaper than the one listed above, at Subaruonlineparts.com.

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  • 1 month later...
I'm getting my transmission mount and gear oil changed on Thursday, and I hope this will solve the problem and that I can report back here with good news. I ordered the stock mount, rather than the STI version. Still, if this part is the culprit, it should bring some tightness back to the driveline. Fingers crossed! This thread has been unresolved for way too long. I'm going to go on a test ride with the mechanic as well before the repair so he knows exactly what I'm talking about; and I'll ask about the rear differential bushings too. Since it's a Sube dealer, maybe they're aware of this problem. Or not.
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