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Discussion Starter #1 (Edited)
I've had this issue for the past couple of months, and it hasn't gotten any worse, but it is still annoying.

When I accelerate from a dead stop, I feel a "bump" coming from somewhere along the driveline. I can't hear anything, but feel two or three of these "bumps" when I'm taking off. I'm wondering if it is a motor mount of diff mount. As far as mods, the CP-E dogbone is the only driveline mod. The car has RPM street springs and a Hypertech flash.

I have had the car up in the air in two separate occasions, and the rear differential feels very securely mounted. I can't move it by hand, and looking at both mounts, nothing is broken. I can only get a good look at the front mount bushing, but it looks to be fine. I can't get a good look at the rear mount bushings.

I'm entertaining the idea of replacing the rear mount bushings with the Turbine Tech parts, and possibly replacing the front diff mount too. The car does see some autocross action, but not a lot, and I don't launch the car hard.

Any ideas? Motor mount or diff mount? I have about 150 miles left on the warranty, and am thinking about dropping the car off at the dealer tomorrow afternoon.

Edit - by up in the air, I meant on jackstands looking over the suspension and drivetrain.
 

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I don't have any ideas, however, some more info might be useful for a response. Year, make, model, engine, automatic 5 speed or 6 speed, mileage.
 

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its a speed6. i would maybe check your rear axles.. if youre doing autoX without any upgraded diff mounts, you mightve broke somethin back there. although with these cars it could be almost anything. passenger side tranny/engine mount, your cpe motor mount (depending on which version. i thought there were problems with the earlier ones), since its lowered it could be your rear sway bar rubbing, the springs might not be seated correctly, etc etc..
im sure others speed6 owners here that have had similar "problems" can chime in.
 

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BigA-
You might have noticed this is the Speed6 section
only 2 years
only 1 engine
only 1 transmission

only 150 miles on his warranty, so just under 50,000 miles if a 2006

and yeah, I'm voting diff mount
 
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+1....Check it out ASAP!!
 

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Discussion Starter #7
Yeah, I think I'll drop the car off tomorrow.

Yes the car is a Speed6. I have checked the axles for signs of damage, but everything looks fine. All of the CV boots are intact. I did a good once over while I was changing the diff fluid last weekend. I'll report back when I find out what the dealer has to say.
 

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Discussion Starter #8
I paid a little more attention while driving home from work yesterday, and while driving to work today. The car doesn't exhibit the clunk, or thud when cool outside. If the car is cool, even on a hot day, the problem doesn't appear until the car is fully warmed up.

I didn't notice anything on my way to work this morning and it was ~87 degrees outside. It was around 102 yesterday while driving home, and I didn't start to notice the problem until I was halfway into my commute, and in stop and go traffic.

I'm not going to take the car to the dealer, but I am going to order the Turbine Tech bushings and install those. I may go ahead and replace the side motor mount and transmission mount too.
 

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Did you push up on the diff? If it moves up and down then it is the forward rear diff mount.
 

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I smell a SU or CPE rear diff mount/brace in your future. Best mod I have done so far. :)
 

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I would swap out that diff mount if I were you asap. If your going to rip the diff apart I would consider going with the entire rear diff mount setup from cpe or su. I thought my bushings were fine too when I eyeballed it but once I took it apart they were torn up. I went with the su stiff diff. Best damn mod I've done to my car. SU rear motor mount is going in next week.
 

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I have the CP-e versoin. And that only cause SU was out of stock. But it was great mod. I alos have all mounts in the motor bay and both of the rear diff mounts. Rock solid. No lag in the drive train
 

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it was bound to get posted here sooner or later...
diff strapping 101 - clicky-clicky

I'm cheap to begin with, and it's a rare day I have to put a real launch on my baby. Fast, yes, just not hard- delicacy & balance + momentum, authority applied as needed.

I added my post to that thread two years ago- I'm still happy with the results, diff bolts never (knock wood) loose, happy happy :)
 

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Discussion Starter #15
it was bound to get posted here sooner or later...
diff strapping 101 - clicky-clicky

I'm cheap to begin with, and it's a rare day I have to put a real launch on my baby. Fast, yes, just not hard- delicacy & balance + momentum, authority applied as needed.

I added my post to that thread two years ago- I'm still happy with the results, diff bolts never (knock wood) loose, happy happy :)
I've thought of this too. I'm going to give this a shot to hold me over until the diff mount comes in and I have a day to swap it out.
 

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Like I said before, when I eyeballed my bushings, they looked ship-shape. Once taking it apart, it was a whole different story. I didn't realize how sloppy my shift feel was. Most likely it was one of those things I got used to. I installed the SU stiff diff and now I feel my shifts tighter. It's like, "Whoa, my shit was pretty jacked, lol!!" Pictures say 1000 words.



I'd also check those two 17mm bolts on the front diff mount from the passenger side and make sure they're fawking tight.
 

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Like I said before, when I eyeballed my bushings, they looked ship-shape. Once taking it apart, it was a whole different story. I didn't realize how sloppy my shift feel was. Most likely it was one of those things I got used to. I installed the SU stiff diff and now I feel my shifts tighter. It's like, "Whoa, my shit was pretty jacked, lol!!" Pictures say 1000 words.



I'd also check those two 17mm bolts on the front diff mount from the passenger side and make sure they're fawking tight.
The really sad part about that is your mount doesn't look like that because it ripped. That is how the mold looks from factory. Mine looked the exact same. Pathetic.
 
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Discussion Starter #18
Anybody have a factory diff mount that they want to unload? Preferrably with the bushings still intact? I have a idea I'd like to try out.
 

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Discussion Starter #20 (Edited)
That as a stop gap measure. Once I swap in something that is a little sturdier, I'm going to see how I can strengthen the OE unit. What I'm thinking of would be similar to what I imagine Ghettospeed was coming up with. My company works with a couple of great metal shops, one of which builds some pretty awesome race car parts.

I had also considered something like Energy Suspension did with the old Honda motor mounts - a urethane insert that fits into the voids of the bushings and stiffens them without transmitting too much vibration or noise into the passenger cabin.

Nothing may come of it, but I'm going to at least see what's possible.
 
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