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RB25 box is in


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I have finished fitting my rb25 gearbox into the 32. Was a fairly easy fit with only minor mod required, all up cost $1500.

Box bolts up fine, with the stock gearbox mount needing some plates welded to it to move it back about 50mm.

Need to fit the rb25 slave cyliner to the gearbox as 32 one is different

A new tailshaft needs to be made as yoke is different, i got the first part of the 33 one with the box and it cost $220 to get lenghtned 600mm.

You need to get a 32 GTR speedo sensor and grind off the gear from the end of it(its moulded on) then fit the gear from the end of the 33 electronic speedo, then the mechanical speedo works fine.

The plugs on the box for the reverse sensor and something else need to be changed

The shifter all goes in the in the same spot and all fits good.

Overal the box feels much better and is able to be shifted fast with not cruncing, only tyre smoke.

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So on my 20 box, when i shift real quick and it crunches, its not un-normal? I was thinking the synchro's were wearing out, and I must admit, ive never missed so many gear changes untill i drove this car. Seems like one of the wost gearboxes around.

Did you sell your old box? How much can u get for a '20 box anyway?

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Luke I actually thought the opposite.

The VS V8's 5 speed i used to miss first to second all the time. always crunched even after the rebuild.

The RB20DET box however I can really slap without a crunch and have been doing so for the last well almost 2 years.

I'm not sure the history of my box but since I bought the car the input shaft bearing is damn loud and whines like crap.

When cold the gearbox is a little grabby going in to second but it doesn't crunch, just feels stiff.

RB25DET gearbox is the way to go though. At least it is one less worry.. :D

Clint... How is the mech. diff? loudish?

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The mechanical diff whines a bit but dosent bother me, there is no other alternaitve to put the power down.

My rb20 box would always crunch, was ok for a while but after i put 235rwkw through it and was smoking decent tyres it had had enought. RB25 box is much better, i dragged my car today and the box was great, occasional slight notch into second but nothing major, ran a 12.8 so im happy.

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Originally posted by -Joel-

When cold the gearbox is a little grabby going in to second but it doesn't crunch, just feels stiff.

Yeah exactly like mine....and when warm, my box doesn't always like changing into 2nd...it's mostly ok though.

When launching or driving hard, it never misses or crunches...i suppose i'm lucky in that way.

Scott.

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Originally posted by -Joel-

It makes you wonder how these 'stock' R33's are apparently pulling high 12's and really low 13's with the very similiar ET's to you Clint.

I know what you mean Joel, i had a 1.893 60ft time and on that run 110mph, and ran the 12.87 seeing what other run and looking in the HPI street drags page there are cars with slower 60ft times and less MPH running the same and faster times, i cant work it out.

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Most RB20 boxes have a nice shift until the sycro's wear out. I got one rebuilt with new syncro's and bearings and it was really good.

If its crunching u need new syncro's. Its not the design of the box , just the abuse from changing fast.

Still im gonna have to invest in a rb25det box soon as the rb20 box keeps breaking .

Clint , i also just got a nismo 2 way mechanical diff . Hows the traction improvement :P:) And the circle work :D :D

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Mechanical is clutch plate LSD, much better powering out of corners, but in a streight line would only make a difference if your is stuffed.

MrMayhem the GTS, GTR use the same cable so i didnt need one, try JMS thats where i got the sensor im sure they had others.

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I think mine is stuffed or on its way as some times it comes on to boost in first and feels like its really pinning you in the seat while the front of the car lifts up considerably (stock suspension), other times it just rev's not going anywhere.. hence open wheeling.

I can't do circle work either unless i really throw it and snap second on a hard lock. :)

I've only tried once though :)

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you should see the circle work with my mechanical diff. it just turns on the one front wheel. purfect circle work in 2nd gear keeping it at 6000rpm:)

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Yeah that's what i thought, the import R31 turbo's have a plate LSD R200 long nose (early type) standard, but mine had a couple of broken plates. I rebuilt it with new plates (more than standard) and it works awsum, better than the Ford 9inch i had in my landcruiser.

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  • 4 years later...

Hey guys

Ive just put a 25box into my r32, i only had to get the yoke from a 33 put onto the r32 tail shaft, cost $230 from the guy ( i forgot his name seeing how my mate sent it there) in wollongong.

Was just wondering if anyone has any pics of what they have done with the cross member,

Thanks heaps

Pete

[email protected]

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Some flat bar extentions welded onto the original bracket, have a look in the Drivetrain forum there should be a much larger thread on 25boxes into 32s.

Edited by bubba
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