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R32 GTS-t restoration - RB20DET Gearbox rebuild

Allister
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Allister Newbie

Allister

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Posted

Hi All,

I'm in the process of trying to restore my old R32 GTS-t M coupe.  Cars never been modified which is rare but it's a factory Auto.  I've got all the OE pedals etc. and a manual box and but it has a destroyed input shaft and some wear damage to the main shaft.  Otherwise the rest is mint with late large gear/multi syncro - trans shop reckon it may have been a good box reassembled with a smashed input and flogged off to me (but it was fairly cheap...)

I'm after as much info about the late OE R32 GTS-t gearbox I can get.  So far I only know the ratios they came with from a Nissan Brochure I have.

Main question is: What is the R32 GTS-t OEM input shaft / counter gear tooth count and does this match a R34 25GT NA gearbox? (- I can possibly get a new OEM R34 input shaft through Amayama.com NZ$475).

I've attached the Service manual Gearbox tooth count info I've found for a KA24DE FS5W71C.  Does anyone have this service manual info for the R32 RB20DE(T) and the R34 RB25DE?  Anyone have the service manual for the R32 GTS-t gearbox at all?  Even in Japanese?  It also looks like there may have been some different gear ratios for R34 RB25's (early/late)?

I've also found that there's a few places in the US doing aftermarket Input shaft/Counter gear sets for their S14 240SX's (US$120) - would these be the correct tooth count/parts for an OEM R32 GTS-t?  Anything about a S14 240 Input shaft that doesn't work for an RB?  I'm also looking at shot peening all the gears to help durability anyway so maybe aftermarket will be ok?

Any help appreciated, thanks!

InkedRatios FS5W71C 240SX SAU.jpg

InkedRatios FS5W71C 240SX SAU2.jpg

GTSBoy Grand Master

GTSBoy

Posted
Posted

I can tell you that  25DE boxes definitely have different ratios compared to RB20DET. I replaced by R32 box with an R34 NA box and one of the ratios was quite noticeably different. Can't remember if it was 2nd or 3rd (was 15 year ago, since replaced with a box strong enough to handle a 25). I recall I was happier with the 25DE ratios - longer legs in whatever gear it was that it was most noticeable in.

Anyway, the only value i have to offer is that it is quite likely that 25DE parts might struggle to mesh with 20DET parts.

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