I agree the 5 speed is stronger than the 6. Just like in the Evo's the 5 speed has the stronger gears. Same size bellhousing with more gears = smaller gears which = weaker gears. Most of the Evo guys swap out the 6 speed internals for the 5 speed when they go for bigger numbers, but for the people who want the 6th gear for economy and not power, it might be a good way to go. Plus my friends 03 GK runs out of gear at like 134 mph he said, whereas the 5 speed in my RD has fuel cut at like 137 and gear run out shortly after.

 

My RD redlines at 125 and I have no fuel cutoff, makes me think, auto. It seems like a lot more work to use an auto case. Not for me. I really don't see why the 6 speed won't fit the Beta. Am I missing something? Did everyone already try this years ago and leave absolutely no info on it that I have ever found? I know mounting it to the subframe would be straightforward since the GK uses both transmissions. At most I would have to fab a couple of mounts. Really the only thing I can figure out is that theres a possibility of trouble dealing with the dual mass flywheel in the 6-speed. linkage shouldn't be a big hassle and I doubt there are any electronics (never saw a manual that had any). Oh one more thing would be the axles. They would possibly need to be resized, but I think a good machine shop can easily do it. I personally would use the chance to go five lug, and use the hubs from the GK. So thats my theory on this subject, and now I'll ask. Does anyone know for sure, possibly even have proof that it won't fit similar to the 5 speed?

 

if you're just wanting to lower RPM/raise top speed, i've heard one of the elantras had a different final gear ratio. the very simple solution it seems would be to swap final gears.

 

I definately wouldn't extend a shaft as it is cheaper to get a new one made. By extending it, you have to weld it, harden the surface again and get it balanced. And it wont have the same strength of a one piece shaft. It will also have a weak point. I am saying this as I work for a major industrial gearbox manufacterer, and extending a shaft is never an option. The only shaftwork we allow for is the reclaiming of shaft seal areas, which is ok because it is a sealing area. The time and money you spend on this project, your better of just buying a 6spd GK.

 

This info is all IIRC and not gospel or anything and should be taken as such...

The GK V6 6-speed is the same as some years of the Nissan Sentra SE-R. The bellhousing is different just the internals are the same. It may also be used on a Toyota model, I don't know. The SE-R LSD works on the GK V6 6-speed. I believe it's a transmission built by a third party drivetrain contractor and provided to Hyundai.

The GK V6 5-speed and GK I4 5-speed are possibly the same internally but have enough differences in the bellhousing to at the very least not swap directly. I think there are significant major differences which would require significant modifications to swap.

The GK V6 5-speed and GK V6 6-speed both have the same bellhousing pattern, which is different than the GK I4 5-speed pattern.

The GK V6 6-speed seems to be physically larger than the GK V6 and I4 5-speeds but I haven't measured them to verify. I don't think there is much chance of swapping the 6-speed's gears into a 5-speed housing.

I have a GK V6 6-speed so if it's helpful I can measure anything that doesn't require me pulling it off the engine or out of the car. I can also compare it to my Accent's 5-speed which does swap with the Beta 5-speed.

There was a Beta II 6-speed GK available in Korea, but it must have been some sort of limited production because it seems to be hard to find, even in Korea from what I've heard.

Feel free to correct anything that I've posted if wrong. smile.gif

Seems to me that importing a Ceed or i30 6-speed would probably be the easiest way to obtain a Beta 6-speed. It would be interesting to see if the Theta bellhousing bolt pattern matches the Beta. It's possible, and if so that would open up some other options, including the Forte Koup's 6-speed.

 

I've heard about the 2.0 6-speed in Korea also, but never found any useful information on it. The Fourte 6-speed is an interesting thought. I'd like to know if that actually works.