First a little bit of background, I am running a mildly tuned 1.9 TSR KR engine with 4 branch, exhaust, filter etc in my Mk2 Golf. The car doesn't frequently get raced around or tracked and is really just used on the weekends to get about or to go to shows and sometimes for a B road blast. As reference I did 4.5k miles in the last 12 months and two of the trips were 600 miles a piece. Historically I was doing a lot of motorway driving (600 miles most weekends) so I swapped out my standard 020 gearbox to a hydro 02A CTN code gearbox from a Mk3 Golf TDI. Now, the gearbox has always made some slightly interesting noises in 1st gear but driven fine even if the gears were a bit long. The noise seems to be getting worse and I am in a position to change it out and as I am not doing the long trips any more I think I am after something shorter in terms of gear ratios however I would like to retain a long 5th gear for the motorway so have been investigating that swap. Initial thoughts are a standard CDA or DPA box from a mk3 golf 16v with a diesel 5th gear. Possibly a 0.658 one which according to my research will give me pretty much exactly the same 5th gear revs as the CTN gearbox did but with a much bigger drop in revs from 4th to 5th. Is that a big problem? I am used to changing down on the motorway for overtaking at the moment so I don't think it will be but any information would be appreciated. Does anyone have any experience with this sort of thing? If so what kind of box did you use and what 5th gear did you use? I have some more modifications that I have been thinking about but I can't imagine the car will ever be above 270bhp even if I carry out a engine swap. As a bit of a swerve ball should I not waste my time and just get the my current box looked at/get a good CTN gearbox and put that in? I'm used to it and as there is a possibility of a considerably large increase in power in the future and I don't want to be chopping boxes in and out all the time because I've put something too short in specially if I am shelling out for a brand new 5th gear. Current box and ratios 02A CTN gearbox 02A CDA gearbox with 0.658 5th gear. For completeness here is a link to swapping 5th gear in a 02A gearbox http://www.myturbodiesel.com/wiki/5th-gear-swap-modification-lower-gearing-on-a-vw-5-speed-transmission/ and here is where I got my gear calculator - http://www.gearboxman.co.uk/inforatios.html
