Drive train Jerking

Since I bought my car I've been experiencing slight jerkings in the drive train when I lay off the gas. The wagon is a 5MT. In my old BMW 540i 6speed, when I lay off the gas, the transition from giving the car gas to no gas was clean and smooth. There was no jerk, the car would simply slow down. With the Legacy, I experience a jerk as soon as I lay off the gas including after a down shift and then it would begin to slow down. The jerking is more pronounced in 1st to 3rd gear and becomes minor in 4th and 5th gear. Could this be engine/tranny mounts or certain bushings along the drivetrain? Or is it just the way the car was designed.

 

**On some downhill roads, I won't feel the jerk at all and I'm assuming it has to do with most of the weight being in the front of the car and the drive train being, in a sense, more "stabilized"**

I feel the same thing in my 05 GT wagon. A friend of mine has an auto and the car is much smoother and quiet. I think the 5mt's in these cars are definitely lacking something in the quality department. On a related note, I highly recommend a short throw shifter (I went with Kartboy, but they all do the same thing) and Momo knob. Getting rid of the vague, rubbery dildo shifter makes the car feel less like an 89 Civic and more european.

I have the same issue. I will be installing new Group-N mounts soon, I'll let you guys know if it helps.

Same problem, pretty much normal with these cars. It's awful in mine and I have ALL brand new mounts.

i have a sedan and have the same problem. Its terrible. I also have group N motor and trans mounts, and a torque solutions pitch stop. the only thing that made a difference was the trans mount cause the stock one is just junk. save your money don't waste time and effort on the motor mounts. all it did for me was make more noise other than that didn't notice a damn thing, engine still moves like crazy. I think its from my LWFW though.

Jerkiness is a part of the Subaru game.

 

I've been driving Subarus for almost a decade now, and it still bothers me. What bothered me the most was driving a M/T diesel VW. Cars don't get smoother throttle transition than that.

Is this issue only with M/T cars or does it exist on A/T cars also?

I noticed my H6 wagon has some engine movement and thats auto. It will be more apparent in m/t because of the physical shifting with the clutch that is going on. If our m/t's had a close ratio gear box and a 6 speed this thing would be a lot smoother. IT frustrates the hell out of me that my engine moves so much even after i replaced the engine mounts and trans mounts

I feel the same thing in my 05 GT wagon. A friend of mine has an auto and the car is much smoother and quiet. I think the 5mt's in these cars are definitely lacking something in the quality department. On a related note, I highly recommend a short throw shifter (I went with Kartboy, but they all do the same thing) and Momo knob. Getting rid of the vague, rubbery dildo shifter makes the car feel less like an 89 Civic and more european.

 

just wait until the torque converter decides to give up on him

it will vibrates like u'r driving on a speed bump

my auto had lots of movement. Had engine mounts checked, had tranny mount checked, had tranny and diffs checked at dealer, had suspension checked by dealer. Added rear diff positive shift kit by Whiteline to hopefully stop the "shifting" of tranny after letting go of the gas to no avail.

 

Mechanic found that the pitchstop bushings are super weak and the entire tranny was moving in place from on the gas/off the gas. Upgraded to the OEM STi pitchstop and it is much better. I opted to stay away from aftermarket pitchstops due to a tendency to increase NVH (noise vibration harmonics, etc).

 

In addition, just had my tune updated again and the drivetrain is much smoother (tuner adjusted the low RPM timing tables and viola', smooth again from idle).

 

Good luck, there are many things that can cause that slop in the drivetrain.

I have this on both of my '08s. I also notice that if you accelerate and then lay off the gas suddenly at highway speeds, the engine sometimes continues to rev without slowing down -- almost like the car has gone out of gear into neutral. You have to blip the gas to bring the rpm down. When it first happened, it was a little unnerving. I felt like the car was running away on its own.

I think it has to do with a poor mount design. The trans is big on this car due to AWD and they only have a little mount holding it up.

I have heard that this is common in manual transmission, AWD vehicles with a viscous center differential. Can somebody confirm or deny this claim?

just to add something more. I installed fred beans center bearing inserts by torque solutions and the whiteline rear diff inserts and it def made a huge difference. Driveline doesn't move nearly as much anymore. motor still kinda moves though...

I guess boxer engine has it's pros and cons.

Pros= no 4 banger sounds better w/ exhaust

cons= drive train jerking

Mine does the same. Makes me think the tranny is going out. I was told by someone cant remember who, that the rear driveshaft carrier tends to have alot of slop in it. Not sure if there is something better out there for that.

What you're describing is completely normal due to the combination of poor design of the mounts in these cars and mediocre electronic throttle mapping. The problem is much less obvious in the automatic cars because the torque converter dampens the transition between on/off throttle.

I hated this and assumed it was primarily an issue with mounts, but found that the issue noticeably improved with the Cobb Stage 1 map, and even more after a custom tune.

 

What you're describing is completely normal due to the combination of poor design of the mounts in these cars and mediocre electronic throttle mapping. The problem is much less obvious in the automatic cars because the torque converter dampens the transition between on/off throttle.

I will say just to comment on this, if you upgrade your mounts do them all together, I replaced my pitch mount first and the older mounts wore it out, now I have to replace it again. Reason being it puts so much more stress on it with the tranny mount/engine mounts being stock. As the stiffer mounts get older you will have more of an issue so perhaps replacing the stock mounts for maybe stock sti mounts is ideal... Agreed???