The opposite problem
I realise this thread is old but I just got my first Alfa, a cheap, high mileage, but lovable 147 jtdm. The acceleration seemed too good to be true, then I discovered it redlined (4.5k rpm) at about 95 mph. Nice Italian mechanic (Gonella in Catford) scratched his head. I tohught it might be missing a sixth, but he said no hardly any had 6 speeds.
Reading the above I reckon I must have a petrol gearbox in my diesel car. Any cheap remedies??? Car was £2k so don't want to spend a fortune.