Technical Ducato gerbox compatibility

[neetch]

Hi! I have a 1997. Ducato with 1.9tD engine. I use it only for transporting my motorcycle so and I have a problem with very short gears, when I reach 110km/h in 5th gear, the engine starts to scream.
I would like to either swap the complete gearbox from another car/van or change gear ratios for 4th and 5th gear.
What would you suggest?
Would any Marea/Bravo/Brava or other gearboxes fit?
Thank you.

 

[neetch]

Anyone?
I've done some research and it seems that Alfa 145 and 155 1.9tD and some other models had the same engine. Is that correct?