Noiseless Chains: Smooth Operation Without Gas

Hello. Some time ago, I replaced the standard clutch on my Golf IV ALH with the clutch from a Golf II G60, along with a solid flywheel.
The following problem exists:

"For example, if I let the car roll in first gear without pressing the accelerator, and the engine speed drops below 1000 RPM, I hear grinding and creaking noises. These noises start exactly when the engine is taken out of the 'coasting' mode because otherwise the RPM would be too low and the engine would stall (around 950 RPM). This happens in every gear, but it's much louder and more noticeable in the lower gears."

Does anyone know what's exactly going wrong with me? Thanks!

Hello,
Does the clutch start to slip due to the uneven torque of the engine?
Best regards,
Günther.

"While I sometimes experience a slight jerk when starting, I still can't quite imagine that the clutch is slipping at that moment. The load on the clutch should be relatively low at that engine speed, in my opinion."

Hm, does anyone have any other ideas? Too bad, I don't either :-/

Hi,

Okay, so if the noises occur during the transition from thrust mode to load mode, and...
Otherwise, if everything around the transmission and drives is securely fastened and nothing can rub, then it sounds like...
Your description sounds like a bearing failure in the transmission.

Best regards, Frank.

Hmm, that wouldn't be very nice...
It actually sounds plausible. However, the squealing only occurred when shifting gears. As soon as I gave it even a little bit of gas, the noise disappeared... how can that be explained?

Hello,

If I understand correctly, the noise occurs only when you transition from power mode to coasting mode (without accelerating), and the engine speed then drops. At that moment, the drive system, including the differential, drives the layshaft, the transmission input shaft, and possibly the engine (with the clutch not depressed). When you accelerate, the power flow is reversed, and the transmission bearings are loaded differently and more heavily. The wheels essentially swap positions; what was driving becomes driven, and vice versa. If this is the case, and everything else seems to be fine, then a bearing in the transmission is likely making the noise. This can happen occasionally, even in new cars with low mileage.

Similarly, it can be a problem if you replace a dual-mass flywheel with a solid flywheel. The torsional vibrations of the crankshaft will be transmitted more strongly to the 'engine' (crankshaft mechanism, etc.), and these vibrations will inevitably also be transmitted to the transmission, making damage to all components that are no longer 'protected' by the dual-mass flywheel more likely. This could even lead to the engine shaking at certain engine speeds.

Best regards,

Thank you for the contribution. This is really very helpful. I had also been thinking something similar. In the long term, a different gearbox will probably be necessary...
What's currently bothering me is that the noise is very irregular, and I have the feeling that something mechanical is scraping. It's not at an excessively high speed, and it's also difficult to identify a specific frequency.


"If it's actually a bearing in the gearbox... what would you do? Buy a used gearbox from eBay for around €350 with 80,000 km? Or send the current gearbox in and get a rebuilt gearbox from eBay (you have to send the old one in) for around €500-€600? Or a new one (which seems way too expensive)? Or just keep driving until it eventually breaks? Could I damage the engine? Thanks, best regards, Bernd."

Hi,

I would put the original flywheel back in and see if the transmission will last a while with it.

Best regards,

Jan.

Seriously, I didn't install the clutch myself.
"I generally tinker with everything imaginable, and even more. In most cases, it works out fine. However, I haven't yet attempted to work on the clutch or transmission. It's always seemed a bit too complex to me. Is it pure witchcraft when it comes to the Golf IV, or can even a reasonably skilled mechanic (who's comfortable with things like the suspension, for example) manage it?"