I too have an 04 Mk2 with the same generic problem. There have been a lot of discussions on the internet in the 8 years since the first question was posted here. A whole new small business in Oldham was built around the problem and buys old Punto gearboxes and sells them on refurbished on eBay!
Mine does so few miles and I am gentle with it (which does annoy some boy and girl racers behind me at traffic lights!).
But with the clutch now compromised and coming up for a test, I'll have to do it now. The reason the clutch slips is because oil has got through the front bearing seal after the bearing has chewed itself up a bit. There has been a development of noises on mine over a number of years. First gear whine was the first symptom. Then second. Then a chirping noise which I reckon was the bearing and/or seal beginning to break up, then third gear whine, then noticeable clutch slip on hills when warm and a bit of judder.
Depressing the clutch when idle stops the noise, so I detect mine is definitely an input shaft bearing.
It is annoying that this is clearly a design fault. My Punto has only done about 75,000 miles even now.
Interestingly from reading around the subject, a variation of the gearbox itself may be used in some Ford Ka's, and possibly other Fiats and other small cars. Mine has a number stamped on the gearbox identifying it as a C514 variant, and is a 5 speed on a Punto 1.2. However, the same problem seems to be reported in 6 speed variants and indeed the replacement bearing kits seem intended for both 5 speed and 6 speed.
Oh well, no use talking about it - I'd better get the box off and have a good look!
Peter, July 2016
