Clunk/Thud when put into first

[DIB2016]

Is anyone experiencing a clunk when put in 1st from neutral? Car has been doing it for a while and just had the clutch replaced. Just want to gauge if its worth putting it in the shop and losing my car for another couple of weeks.

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[datadatum]

Yes. My understanding is that this is normal for the differential engagement.

 

[SVTinAR]

There have been a couple of threads on here about the "clunk". Seems to be fairly normal and a few theories on it's origin but no conclusive findings. Some have said driveline slack take up. Others the two piece driveshaft. Hydraulic TO bearing. It is strange because nothing is moving (except engine) when at a stop and the clutch is pushed in, shifter moved to gear and then "clunk" or "thud" prior to starting to release the clutch. Mine does it too but gotten used to it.

 

[Bird of prey]

Clutch adjustment ?

 

[BlackandBlue]

There is always some torque being transmitted across the driveline even when the clutch is pressed in.

The pilot bearing transmits some torque, TO little bit, and sometimes the clutch drags ever so slightly. As soon as you put it in gear it takes all the slack out of the system.

In my friends 16 350 we could never isolate the sound. You could put a mechanics stethoscope on the half shaft and sometimes it seemed like it was right there and other times it seemed way up in the drive train. Our theory was it was just depended on how the system settled from the last engagement. His was pretty loud.

 

[SVTinAR]

Well, lets see - when the transmission sliders are all in neutral and the clutch pedal released the only thing moving past the engine is the input and the countershaft gear set because all the slider syncros are disengaged. The main shaft is only affected by what ever drag the rollers inside the input impart on it - not much. When the clutch pedal is pushed down, the discs are released which allows the input shaft and countershaft to spin down to a stop. Pretty much isolates the rest of the drive train. Then the shifter is put in first which moves the synco slider over the first gear blocking ring and gear engagement teeth. That seems to be when the thud or clunk is heard. Could be that motion we are hearing/feeling but it shouldn't be of such action to create a thump - hasn't in any other manual transmission I've owned and I have several. It could be that the twin clutch discs have enough parasitic drag on the intermediate plate and pressure plate that the input and countershaft do keep spinning somewhat even when the pedal is pushed down which should disengage everything. And the thud is actually the sycro action of the slider engaging the blocking ring teeth and suddenly stopping the spin the countershaft gear set.

 

[onlyturbo]

My 2015 has the clunk as well, it is intermittent. To avoid it, quickly go into second gear, then engage 1st.

 

[Voodoo Velocity]

From what I read, there is a mechanical clunk inherent to these cars. I read the same for manual GTs. I have heard a slight clunk, usually shifting from 1-2 at low speed (ie. maneuvering in a parking lot). I can hear and feel there is some mechanical engagement going on back there. I have read it may occur in all gear changes, but at slow speed it is perceptible without road / tire / higher rpm engine noise. Considering this car is designed for track capabilities, I accept there is some trade off in what may be a refinement expectation vs track capable robustness.

 

[MikeR397]

Sometimes a clunk, but more often i seem to have a sticky synchro going from neutral to first more often than not on my 4500 mile car. It’s like two levels of sticky ness before the gear slots in first from neutral.

 

[torque124]

I have the same clunk... my Beemer does this at times too. Normal.

 

[Sagittaria]

Normal with a manual car and an IRS... look up "Cobra Clunk" on svtp. This has been griped about for over a decade - especially so with the 2003 Cobras.

 

[SiMuL]

Well, lets see - when the transmission sliders are all in neutral and the clutch pedal released the only thing moving past the engine is the input and the countershaft gear set because all the slider syncros are disengaged. The main shaft is only affected by what ever drag the rollers inside the input impart on it - not much. When the clutch pedal is pushed down, the discs are released which allows the input shaft and countershaft to spin down to a stop. Pretty much isolates the rest of the drive train. Then the shifter is put in first which moves the synco slider over the first gear blocking ring and gear engagement teeth. That seems to be when the thud or clunk is heard. Could be that motion we are hearing/feeling but it shouldn't be of such action to create a thump - hasn't in any other manual transmission I've owned and I have several. It could be that the twin clutch discs have enough parasitic drag on the intermediate plate and pressure plate that the input and countershaft do keep spinning somewhat even when the pedal is pushed down which should disengage everything. And the thud is actually the sycro action of the slider engaging the blocking ring teeth and suddenly stopping the spin the countershaft gear set.

This sounds the most plausible to me.

 

[xXANCHORMONXx]

Normal.

 

[TomcatDriver]

Normal. And if you habitually put it in second before first when at a stop, it makes the clunk in second also. It seems to make it less if you stay in gear with the clutch in until at a complete stop instead of going to neutral.

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