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hey guys. just bought a cefiro, with a rb25DET, but still with the rb20box. its starting to make a few noises.

just wondering what my options are, i guess a rb25box would bolt up nicely, but how about a vg30box? any stronger? just wanna be prepared for when the rb20box breaks.

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The VG gearbox would probably just need an adapter plate or something of the likes and will hold up to about 450hp, it has fairly beefy internals similar to RB25DET box afaik but I believe the RB box would be slightly better. Also, the only difference between turbo/na VG boxes is the TT flywheel is slightly larger.

GTST, GTT, GTR and VG30 are virtually the same box, the GTR is only stronger as the output shaft has more support bearings due to the transfer case... therefore recieves less off centre loads.... internally identical to GTST... i mix and match parts a bit. R34 GTR is getrag totally different. R34 GTT same as r33 only has a few niceties inside but no stronger.

  • 3 months later...
  • 1 year later...
So, are the internals from a R33 GTR interchangeable with the R33 GTST?

yeah i have interchanged gears and syncros between these two boxes (second and third gear), amazing how the GTR box goes for less then the rb25det, its the same!

the late model r33 gtr box has a thicker input shaft in places, so a few of the bearings are different. i didnt swap this over but it also looks straight forward

dont be scared of manual boxes they are pretty easy to do, just need the right tools, auto boxes on the otherhand NFI

hey shoei

got a link or something with a step by step on how to dismantle and assemble a rb box?

i have tired to take the gears and syncrhos out myself but got stuck as the gears and/or syncrhos would not come off

thanks for any help

=)

http://www.300zx-twinturbo.com/cgi-bin/manual.cgi

give it a shot, and let me know how you go, i messed up my first rebuild, third gear had a vibration after i put it back together, best thing is you got noone to blame but yourself

Edited by shoei
hey guys. just bought a cefiro, with a rb25DET, but still with the rb20box. its starting to make a few noises.

just wondering what my options are, i guess a rb25box would bolt up nicely, but how about a vg30box? any stronger? just wanna be prepared for when the rb20box breaks.

thought the 25 box was 1 of the stronger ones, bolt up with decent clutch u'll have no probs

the vg box is very similar to the rb25 the only thing that wore on my rb25 is the synchrons (didnt like my gear changes lol) stronger boxes are the gtr and ive also heard that supra boxes are very strong too

correct me if im wrong don't supras and r34 Gtr have the same box ? a 6 speed getrag

GTST, GTT, GTR and VG30 are virtually the same box, the GTR is only stronger as the output shaft has more support bearings due to the transfer case... therefore recieves less off centre loads.... internally identical to GTST... i mix and match parts a bit. R34 GTR is getrag totally different. R34 GTT same as r33 only has a few niceties inside but no stronger.

wow didnt know that makes me want a rb25 even more ..

so Mr URAS how much rwkw can a rb25 box take then ?

use a rb25 box for now.

you can safely run about 300kw's at the wheels with these.

their are 2 at the track with 320kw plus with a rb30 bottom end and they are holding up just fine.

not sure how much further you would go though, once your going more than that save up for a pdg gearset or simular

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