Issue 1: For some time now I've been a little unhappy with how much "driveline slop" I have in my car. I sit in slow moving traffic regularly, during this time I am often in first or second gear and the switch from throttle to no throttle or throttle to no throttle is jarring. The entire car jerks really annoyingly. Said differently, going from crusing at 2500 rpm in first or second gear to engine breaking feels very abrupt.

Issue 2: Another annoyance occurs when I need to move the car forward a little bit but never fully release the clutch. When I get rolling I usually press in the clutch, after doing this I hear and feel something shaking, as if something heavy is oscillating back and forth and isn't stopping. I suspect it is the motor or transmission.

The car: My car has a Southbend single piece flywheel (~24lbs) and stage 2 clutch. I believe the lack of the dual mass flywheel might contribute to this, but I kinda think my car did this before the flywheel changed. Aside from that the rest of my car is stock.

Questions: I suspect one or more of the transmission mount, motor mount or diff bushing are in need of replacement. I've looked at the diff bushing, it doesn't appear to be leaking silicone goop. Is it possible that all the goop has leaked and dried out over the past few years?

I've taken a look at the motor mounts from the top, they didn't seem horrendous. I'll inspect them from the bottom when I look at the tranny mount. What should I look for?

The transmission mount, what am I looking for on this? Worn rubber? Is it even visible without disassembly?

 

you would know if the diff bushing was leaking. even if it did "dry up" you would still see the black streaks on the back of your diff cover. I also have this "driveline slop" and I just had my diff bushing replaced under warranty. it is much improved but ill most deff be getting the white line kit for it soon.

 

There are currently no streaks on my diff cover (used to have some dark brown ones when I bought it, but I washed them off). The bushing facing the rear of the car is not obviously ripped or leaking. I want to crawl under and look between the diff and subframe for streaks or leaks there.

 

Doug, is this your first manual? Most manuals exhibit this to a varying degree. In an auto you have the torque converter that also acts as a damper to absorb this. On a manual it's a direct connection. Good throttle control minimizes this. Maybe a TB cleaning would help too.

Issue 2 I would have attributed to a dual mass flywheel, but given the aftermarket parts, I'm not sure. Could it be your clutch technique, too much clutch release?

 

I have an 08 when I bought it, it had 17k miles and I have always experienced those types of jerks and driveline movement (annoying as hell) all stock clutch and flywheel. If you can get them inspected and find some sort of improvement let us know!
How many miles does your car have?

 

Yes, this is my first manual. This has been irking me more ever since I drove a stock 2010 G37s w/ half as many miles that was much less abrupt.

When you say too much clutch release, I generally do find it happens when I press the clutch down quickly. I expect some weight shift when I aggressively move forward small distances and then press the clutch down quickly, but the oscillating should be damped or settle down quickly.

130k km (80k miles) on a 2008 G37s 6MT.

 

[QUOTE=Dough1397;3809089]There are currently no streaks on my diff cover (used to have some dark brown ones when I bought it, but I washed them off)QUOTE]


more than likely you have already popped the bushing and there is nothing left to leak.

 

Why did you change the clutch and flywheel with 80k on the trans? If the factory clutch was worn maybe the car was abused.

 

CSC failed at ~60k miles, figured I'd just bite the bullet and get a new clutch.

 

Oh yeah, issue 1 gets worse after the car has been driven for a bit. First thing in the morning is a little better than after driving for 30 minutes.

 

I got real close and personal with my diff bushing this weekend. Here is a picture of it with all wheels on level ground. The weight of the diff is compressing the lower bladder and stretching the upper bladder. There are some fine cracks in the rubber.


The lower compressed bladder is soft enough that I can push it in with my index finger as seen in this video. I suspect a fluid filled bladder would be much firmer, however I don't know for sure. I would love if someone could make a similar video with their stock and newish. Opinions are always welcome!


I have a feeling I would sleep happier if I upgrade to the Whiteline bushings, but that is a project I'd like to put off til next summer.

 

Issue 2: Another annoyance occurs when I need to move the car forward a little bit but never fully release the clutch. When I get rolling I usually press in the clutch, after doing this I hear and feel something shaking, as if something heavy is oscillating back and forth and isn't stopping. I suspect it is the motor or transmission.

I have this same problem. At slow speeds when I clutch in sometimes it sounds like metal pieces slapping each other.