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Rb25Det Series 1 V Series 3 Gearbox


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Hi Guys,

I am looking at upgrading my R33 series 1 RB25DET gearbox, I am looking at either a Series 3 or even a straight cut gear set. My question is;

What are the differences between Series 1 and series 3 boxes?


How do you identify them externally (Markings and model numbers etc)?

Thanks in advance peeps.

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I know Series 3 GTR gearboxes are stronger then their earlier brothers...

But GTST wise there was only ever Series 1 and Series 2 :/ - and I wasn't aware of any differences gearbox wise for them.

I could be wrong tho...:/

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Yeah this is where my confusion lies. As far as I know all R33 Gts-t manual boxes are the same. So there was no real series 1 or 2 box let alone series 3

Unless your talking GTR boxes as questioned above

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See, SAU Rocks!

I was skeptical at first, thinking the same as you guys, I had heard of a series 3 for GTR, but not GTS... I wondered if perhaps it might be from a R34 GTT???

Some more research needed.

Cheers guys!


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And as far as I know it was the syncros which were strengthened in the S3 GTR boxes.

I thought one of the gears or maybe shafts was an updated (better) version. Thought I remembered seeing something about this, but Im no expert on GTR boxes, so this could be 100% wrong lol

but R33 S1 and S2 boxes are identical, R34 boxes..... Not so sure, but think there the same also (early versions at least)

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Yep, you guys are right! definately no series 3 GTS box... spoke to the original source again and they confirm that for some reason they starting thinking GTR even though I had said RB25DET... lol.

Thanks for your help guys.


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Wouldn't be much of an upgrade anyway...the difference between GTR boxes is buggerall...they still all blow 3rd gear when pushed hard enough. Better off investing in an aftermarket gearset.

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