Manual Trans. Thud when shifting

[woofwoofdroolyface]

Here's an interesting video of the subframe movement under acceleration and a mild launch from Steeda:

[ame]

It'd be great if we could get a video like this of putting the car in first after decelerating to a stop and verify that there is rear subframe movement. The BK054 replaces the bolt and fills the void in the mount in the left of the frame next to the sticker ending in "ARC".

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[WeinerDog]

When they say competitor,who and what product are they talking about? The bk054 doesn't look like it's permanent.

 

[Jewishthunder]

When they say competitor,who and what product are they talking about? The bk054 doesn't look like it's permanent.

That video doesn't look like it's comparing the right product. Plus, you can still see that subframe bolt moving pretty violently.

 

[woofwoofdroolyface]

They're not talking about the BK054 and the Steeda Differential Bushing Inserts specifically in that video, they're trying to sell other IRS components to stop wheel hop. But it's a great video to illustrate how much movement there is in the rear subframe that can cause the thud.

 

[woofwoofdroolyface]

Actually here's a better video specifically on the mounts we're discussing from Steeda:

[ame]

 

[Jewishthunder]

Steeda's wrap up comparisons are pretty hilarious. It doesn't actually compare it anything real that I've seen? Definitely not comparing it to BMR's pieces. They're so assumptive lol.

 

[woofwoofdroolyface]

Steeda's wrap up comparisons are pretty hilarious. It doesn't actually compare it anything real that I've seen? Definitely not comparing it to BMR's pieces. They're so assumptive lol.

Yeah, it's definitely an advertisement but it shows how bad the stock mounts are. BMR mounts will have less movement than the Steeda poly mounts.

 

[fogus]

Vid here demonstrating the issue: [ame]

Watch at 3:09 ( ) and you'll actually see the whole image vibrate as the car lurches with the camera mounted to the proclip.

 

[Asharus]

if you guys google first gear thud, clunk or thump, you'll see that it's not an isolated issue to s550s.... anywhere from new to old bimmers, subaru/scion BRZ/FRS, etc.

 

[WeinerDog]

if you guys google first gear thud, clunk or thump, you'll see that it's not an isolated issue to s550s.... anywhere from new to old bimmers, subaru/scion BRZ/FRS, etc.

All the more reason we shouldn't have this issue in these cars. It's funny, when it happens at a stop going to first I don't really care. It's much, much worse going 1-2 or 2-3 in my car.

I've ordered the Steeda kit and will have it installed ASAP. Fingers crossed. Decided against the BMR as apparently there is an issue and they are redesigning their kit.

 

[FordTechOne]

Vid here demonstrating the issue:

Watch at 3:09 ( ) and you'll actually see the whole image vibrate as the car lurches with the camera mounted to the proclip.

You can't be serious.

EVERY vehicle with a manual transmission will do that. Here is why:

When the transmission is in gear with the clutch depressed, the input shaft is directly engaged to the wheels. Therefore, it is stationary. As you change gears, all of the internal components in the transmission remain stationary.

When you let the clutch out in neutral, you spin up the input shaft to the engine speed. When you release the clutch, the input shaft continues to freewheel since the transmission is in neutral.

When you place it in gear with the input shaft freewheeling, the synchronizer needs to match the speed of the input shaft with the speed of the gear being selected. Therefore, the synchro needs to reduce the speed of the input shaft to zero RPM. This is accomplished through the use of a blocking ring, synchronizer hub, and shift fork. The blocking ring contains a friction material (carbon fiber, bronze, composite, etc) that acts as a clutch to speed up or slow down the gear. The synchronization of the speed gear is the clunk noise and resistance you feel in the shifter when you engage the gear. Once the input shaft is stationary, the gear can then be engaged. All that happens in the couple tenths of a second it takes for you to move the shifter from neutral to 1st gear.

 

[WeinerDog]

You can't be serious.

EVERY vehicle with a manual transmission will do that. Here is why:

When the transmission is in gear with the clutch depressed, the input shaft is directly engaged to the wheels. Therefore, it is stationary. As you change gears, all of the internal components in the transmission remain stationary.

When you let the clutch out in neutral, you spin up the input shaft to the engine speed. When you release the clutch, the input shaft continues to freewheel since the transmission is in neutral.

When you place it in gear with the input shaft freewheeling, the synchronizer needs to match the speed of the input shaft with the speed of the gear being selected. Therefore, the synchro needs to reduce the speed of the input shaft to zero RPM. This is accomplished through the use of a blocking ring, synchronizer hub, and shift fork. The blocking ring contains a friction material (carbon fiber, bronze, composite, etc) that acts as a clutch to speed up or slow down the gear. The synchronization of the speed gear is the clunk noise and resistance you feel in the shifter when you engage the gear. Once the input shaft is stationary, the gear can then be engaged. All that happens in the couple tenths of a second it takes for you to move the shifter from neutral to 1st gear.

Thanks for the info but why should I or any of us care about all that? I don't care much how my air conditioner works...as long as it works.

Why do I have to hear this obnoxious sound?

 

[FordTechOne]

Thanks for the info but why should I or any of us care about all that? I don't care much how my air conditioner works...as long as it works.

Why do I have to hear this obnoxious sound?

Because that's the way mechanical devices work.

If you don't like it, then walk. Ignorance of the laws of basic physics is not anyone's problem but your own.

 

[WeinerDog]

Because that's the way mechanical devices work.

If you don't like it, then walk. Ignorance of the laws of basic physics is not anyone's problem but your own.

:lol:I and others here have had many other vehicles with manual transmissions that don't do this. They were/are "mechanical devices", no? How come some do it and others don't?

You may be 100% correct about what's going on inside the tranny but how about coming up with an idea of how to stop the sound getting into the interior instead of berating those of us seeking a solution?

What do you think could isolate this sound?

BTW, do you really work for Ford?

 

[Asharus]

that's why i havent given any thought to this thud when i heard it, because i understand what is going on, and it's not just a "black box" to me.

the only reason i have given this any thought is because of this thread. it's obviously a concern to everyone else, and it's been a pretty interesting 50 pages so far....

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