can you change a 5speed gearbox and replace it with a 6 speed gearbox

[jovi4]

can you change a 5speed gearbox and replace it with a 6 speed gearbox?
would it damage the engine etc. and would it fit exactly on to the engine?

its a grande punto 1.4cc 16v t-jet {turbo} 2007 & petrol

thanks

[The-HouseHusband]

If the gearbox was designed for the punto then you may be alright. However you could have a few problems in the way the gear selector connects into the car and also the speedo would not be calibrated for the gearbox/final drive so could give false readings.
Just out of interest why would you want to change unless the old one is damaged, economy is not going to be changed much and performance will not be noticeably different either.

[johnk]

Why would you want to change, the top and bottom ratios are the same, it just means more gear changes and becomes a pain!

[jomifl]

You only need a 6 speed box if the engine has a peaky torque curve, it won't make any difference if the engine is designed for road use.