I've made the very 1st modification to my '64 Bug... swapping the 1200cc out for a 1600cc dual port. Now I've been told I have a "6 volt" transmission/transaxle with a lower 4th gear and that I need to swap it out as well for a "12 volt" swing axle ('67/'68) trans to optimize the new 1600 and improve crusing speed. TRUE? If true, can't I just have the 4th gear replaced or do I indeed need an entire new/rebuilt trans? Lastly, if a new trans is required, any recommendations as to a source/vendor? I am keeping the 1200cc and would keep the orig trans too so no core would be sent back.
Thanks for ANY assist!
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Here's a reply from Mike at Stuff VW Transaxles;

Yes you can change just 4th gear. The down side is you still need to rebuild the transaxle. The gears are put together so anything you do to the transaxle you have to take it completely apart. You can grind out the old transaxle in the bell housing to fit the new flywheel.

Mike Watson
Stuff Classic VW Transaxles
1-866-VW-STUFF or 897-8833
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Hi Ron,
I would just leave it and use it as it is for a while to see if You think it needs to be swapped over for another transmission... You will have to grind out the gearbox housing for the 12 volt flywheel if You are changing to 12 volts as the 6v & 12 v flywheels are different sizes and the starter motor ring gears are not interchangeable..
So, keep it 6v with 180mm flywheel & clutch and 6v starter motor or change to 12 volts with 200mm flywheel & clutch & 12 volt starter motor & 12 v starter motor bush..
OR - change to 12 volts BUT keep using the 6 volt starter motor, 6v clutch etc... Decisions...

Y our gearbox final drive ratio is 4.375 - 1
and the 68-70 final drive ratio is 4.125 - 1

Best of Luck

Lee Noonan -- 68AutoBug -- Australia --

Lee Noonan
68AutoBug - helping keep air cooled Volkswagens alive in Australia & around the World -

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Hi Ron,
I have a '61 with the same setup you have now. I'm not bothered by it. Around town, I treat it like I'm driving a 3 speed with 4th as an overdrive, so don't really use 4th unless I can sustain 35mph+ for a reasonable length of time. You can hover around 30-40mph in 3rd without feeling that you are over-revving. On the highway you need to anticipate early for hills when in 4th and compensate with throttle accordingly.

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