I've noticed a thunk from the rear end when I put the shifter into 1st gear (with the clutch in) from a standing start. Is this a "they all do that" thing for the S2K (I've had mine 6 days now)?

I've had a couple of older Alfa Romeos with limited slip rear ends that did a very similar thing, which was considered normal for the car. Any input would be appreciated so I don't go screaming back to the dealer like a nancy-boy.

Rich Lasner
03 S2K Silver Metallic/Black
Santa Monica CA

 

Depends on how much of a "thunk". I don't think it is normal. Have you checked your spare tire (make sure it is bolted down tightly). Same question for the tools in the bottom of the trunk.

 

I often get a thunk when I have the car in neutral while stopped with the clutch out, then depress the clutch and engage the gear.

The reason for this thunk has to do with how the gearbox is set up. The clutch has two parts to it, one is attached to the engine crankshaft, another goes into the gearbox. This second shaft can spin freely (when in neutral) or is "engaged" via gears to the rear wheels. However, when the clutch is engaged, this second shaft *must* spin at engine rpm or slip.

Thus, when you have the clutch out in neutral, this shaft/clutch half is spinning at idle rpm, because the engine is spinning it. When you push the clutch in, the clutch disengages, and the shaft is essentially free-wheeling. When you engage the gear, if the shaft is still spinning, the synchromeshes in the gearbox have to accelerate the shaft to wheel speed, which is zero when stopped. *That* is the thunk I was talking about in the first part of the post.

The "solution"? Wait a few seconds after pushing the clutch in before engaging the gear.

The way to check if this is the thunk is to drive your car. At a red light (or anytime after stopping), put the car in neutral and let the clutch out. Then push the clutch in, followed (within a second or two) by putting it in 1st. You should hear a "thunk". If this is the same sound thunk you're hearing, then there is no problem. If this is not, there may be something else going on (which might require a mechanic to look at).

Someone mentioned that this shaft piece weighs 18lbs. I'm not sure if that's the right number, but it is a fairly hefty piece of metal, if I recall it right.

 

[QUOTE]Originally posted by hoof
[B]I often get a thunk when I have the car in neutral while stopped with the clutch out, then depress the clutch and engage the gear.

The reason for this thunk has to do with how the gearbox is set up.

 

ive actually found that if you slowly push the shifter into gear then the thump will either be minimized or you wont even feel it. i guess depending on how fast you engage the gear the more youll feel the thumk

 

whew.. i thought that thunk meant i needed a new trans. mount.

 

Good to know. I have experienced the same clunk when putting it into first. I did notice that waiting a second would prevent the clunk from happening.
Glad I have one less thing to worry about now.

 

Felt the same and didnt ask because someone would flame me for not searching when I did and couldnt find anything.

 

Mine clunks too! I love this forum because just when I think something on my one-month old AP1 is about to give up the ghost, you guys are here to tell me it's ok and nothing to worry about.

This car really seems to generate its fair share of concerns for clutch, transmission, differential, and gearbox noises or phenomenon.

I am happy to say my car with about 24k miles exhibits nearly every noise that I have ever read about on s2ki:

1. Sitting at a light with clutch engaged (pedal up), I hear a whirring, clickety clack sound. Throwout bearing or gear rollover I believe. I've had other cars do this so not too concerned about this one.

2. When I put the clutch in to put it into first, I hear the clunk that inspired this topic. Now I know I should wait a sec.

3. When the car is cold, first to second and second to third gears always have a minor "graunch." The gears never actually grind, they just feel like they are on the verge of doing so. I find slow shifting and easing it in between the gates helps until warm. I got the fluid changed out with Honda's latest MTF formulation when I got the car.

4. When I am shifting between the gears, my clutch makes a "growling" sound when engaging and disengaging.

5. When decelerating from high revs under compression, I hear the infamous clutch buzz.

6. And finally, speaking of clutches, I find mine has multiple personality disorder. This car can be a bit of a challenge to drive smoothly but maybe it's because I need to get used to "someone else's" clutch engagement point.

I have manual transmissions since I've been driving and I am one of those people that likes to let the clutch out slowly while barely using gas to get away from a stop. The S does not always like that approach. Sometimes it works as smooth as butter. Other times it nearly stalls so I need to use more gas. Then at the next light I'll use more gas and this time the clutch slips as I let it out so I feel I need to hold back at the next start. And so its a vicious cycle but I think its more me than the car!

My car is still covered under the CPO warranty but it really just sounds like these are all characteristics of the S--particularly the AP1. I am usually pretty anal about stuff like this but I have really taken a wait and see approach to these little issues, because in spite of all its little noises, it is so endearing to drive. I would rather enjoy it than waste effort worrying about it.

 

My car thunks from time to time until I searched and found out it's normal.