Gearbox

[petethepom]

The bad news is that the gearbox in my r33 gts n/a is dying, redline heavyshockproof is not helping.

The good news ( hopefully) is that the gearbox off a 200sx is the same.

Is that right?

[Eug]

as far as i'm aware, the r33 gts25 gearbox is the same as an r32 rb20det

[petethepom]

That might be right.

When I was told that the n/a had the same gearbox as the 200sx s14, the guy said that my gearbox ,unlike the gtst, had the oil filler hole on the passenger side.

To be honest when I replaced the oil on my gearbox I filled it through the reverse gear switch which is on the drivers side as there was no filler on that side ( I didnt think to look on the other side!).

I have just seen a picture of the 200sx gearbox and it has the swich in the same place so I just need someone who maybe has changed a gearbox on a r33 n/a to confirm this is the same box.

I think that the 200sx may have the rb20det engine in it which , I think puts out about the same power as the rb25de so it makes sense.

I was told that the 200sx had these gearboxes in until 1999.

I dont want to chase a gtst gearbox if it doesnt fit and a 200sx gearbox is supposed to be easier to come by.

As the n/as seem to be very popular in Australia maybe someone out here knows.

[Eug]

since you're from england, i'm not sure what you designate to be the 200sx.

but here in australia, the 200sx is the s14/s15 with the sr20det motor. all the silvias use the ca18de(t) or sr20de(t) engines.

i have never heard of the rb gearboxes being interchangeable.

[petethepom]

I was told the gearbox was the same for the 200sx between 1994 and 1999. I think that up to 1994 the 200sx was the s13 and between 1994 and 1999 it was the s14.

If anyone has a r33n/a with a rb25de engine in it and have changed thier gearbox they would probably know.

I know there is a lot of non turbo skylines out here .

[adam87]

i know you can put an RB20 box with an SR20 bellhousing behind an sr20. i would assume it would work the other way.

however a CA18 box with an RB20 bellhousing didnt bolt straight up behind an rb20 or 25 due to being an inch too long. also RB30 boxes also work.

to see if its going to work get someone to measure an SR20 gbox for you and compare it to yours. the bellhousings are all interchangeable between SR, CA and rb20

Edited January 26, 2008 by adam87

[342Four]

dont think so

i think you will find that the bolt pattern is different

if they were the same i think you would find a lot of silvia owners going to a stronger rb25det box then the notchy 6 speed on the s15 and the weaker input shafted s14/s14a items

like eug said, the rb20det box is the same as the rb25de

rb20det's came out in r32 gts-t's, cefiros, laurels, r32 gts-4's (but in awd configuration) and a few others that i cant think off atm

[adam87]

dont think so

i think you will find that the bolt pattern is different

if they were the same i think you would find a lot of silvia owners going to a stronger rb25det box then the notchy 6 speed on the s15 and the weaker input shafted s14/s14a items

like eug said, the rb20det box is the same as the rb25de

rb20det's came out in r32 gts-t's, cefiros, laurels, r32 gts-4's (but in awd configuration) and a few others that i cant think off atm

what i said is from personal experience. i did not mention anything about 25 boxes, rather sr20,rb20 and ca18 boxes.

many silvia owners are using 25 boxes but the bellhousing is a cut and shut and so is the tailshaft.

[342Four]

okay - there you go

put it this way - it would be much easier to source a 2nd hand rb20det or rb25de box then do a cut and shut bellhousing mod to fit a sr20 box behind a rb25

[petethepom]

so what you are saying is that the 200sx s14 has rb20det engine and the rb20det engine would have the same gearbox as the rb25de.

Ive got a rb25de engine so the 200sx s14 box should fit mine.

Yeah???

[petethepom]

Sorry the 200sx has a sr20det engine ( 4 cylinder ) not a rn20det!

[adam87]

so what you are saying is that the 200sx s14 has rb20det engine and the rb20det engine would have the same gearbox as the rb25de.

Ive got a rb25de engine so the 200sx s14 box should fit mine.

Yeah???

no the 200sx has an SR20 engine.

it should fit but you will need to take your existing bellhousing off and put it on the sr20 gearbox. before you buy the SR20 gearbox have the owner measure it up for you

okay - there you go

put it this way - it would be much easier to source a 2nd hand rb20det or rb25de box then do a cut and shut bellhousing mod to fit a sr20 box behind a rb25

you dont seem to understand what im saying. he can bolt his current RB25de bellhousing onto the SR20 gearbox.

theres no need to cut and shut bell housings for this application.

all he needs is an SR20 box with an RB20 or RB25de bellhousing. you then take the SR20 bellhousing off the SR20 gearbox and bolt the rb20 or rb25de bellhousing on to the SR20 gearbox.

All SR20, CA18 and RB20(RB25de) bellhousings are interchangeable between gearboxes.

all i recommend he does is have the length of the SR20 box measured from the sandwich plate in the middle of the box to the end where the driveshaft bolts in.

Edited January 26, 2008 by adam87

[petethepom]

Sounds like it can be done.

Thanks

[342Four]

no the 200sx has an SR20 engine.

it should fit but you will need to take your existing bellhousing off and put it on the sr20 gearbox. before you buy the SR20 gearbox have the owner measure it up for you

you dont seem to understand what im saying. he can bolt his current RB25de bellhousing onto the SR20 gearbox.

theres no need to cut and shut bell housings for this application.

all he needs is an SR20 box with an RB20 or RB25de bellhousing. you then take the SR20 bellhousing off the SR20 gearbox and bolt the rb20 or rb25de bellhousing on to the SR20 gearbox.

All SR20, CA18 and RB20(RB25de) bellhousings are interchangeable between gearboxes.

all i recommend he does is have the length of the SR20 box measured from the sandwich plate in the middle of the box to the end where the driveshaft bolts in.

gotcha now

now the next thing - it might work, but would it be actually worth it???

the rb's are 6 cylinders and put out more torque then the sr20 4 cylinders

wouldnt it be more economical to spend a bit more dosh to get a 2nd hand rb25de/rb20det box then potentially break some sr20 boxes???

[inthisglass]

yeh im with ash

i just dont see the point in buying a new gear box if your only going to used the bell housing or weaker internals of the sr20 gearbox?

just spend a few more dollars and buy a stronger gearbox that will fit without modification.

[adam87]

internally rb20 ca18 and sr20 gearboxes are the same. plus it will be going into a non turbo engine with less than 200hp more than likely

[petethepom]

Where I am you can pick up a 200sx gearbox a lot cheaper than a skyline one.

Also there are a lot more of them around so yes if I could pick up a decent Skyline box it would be the best thing but if a good 200sx box will fit, great!

Just one other thing. After I found that I did not have a gtst box I also found out that my box holds about 1.5 litres less than the 4 litres I put into it.I drained a load of oil out and the boxs seems to crunch less. Its gone from crunchy to a bit notchy( which I can live with).

Hopefully it will stay that way, if not I can fall back on what I learned here.

Edited January 28, 2008 by petethepom

[R34GTFOUR]

no the 200sx has an SR20 engine.

it should fit but you will need to take your existing bellhousing off and put it on the sr20 gearbox. before you buy the SR20 gearbox have the owner measure it up for you

you dont seem to understand what im saying. he can bolt his current RB25de bellhousing onto the SR20 gearbox.

theres no need to cut and shut bell housings for this application.

all he needs is an SR20 box with an RB20 or RB25de bellhousing. you then take the SR20 bellhousing off the SR20 gearbox and bolt the rb20 or rb25de bellhousing on to the SR20 gearbox.

All SR20, CA18 and RB20(RB25de) bellhousings are interchangeable between gearboxes.

all i recommend he does is have the length of the SR20 box measured from the sandwich plate in the middle of the box to the end where the driveshaft bolts in.

as adam87 said, the actual gearbox side of things are exactly the same, same internals, same strength. Its only the bellhousing which differs as obviously the bolt pattern on a sr is different to a rb. Change the bellhousing over to suit the rb and it will work fine.

[petethepom]

Once again thanks you guys for your knowledge!!

[RBwhatever]

I noticed you said you filled your GB with shockproof heavy gear oil.

Wouldn't it have been better to use either a Shockproof Lightweight or MTL or MT90? Most guys over here that use redline use either of those for the GB, not heavy weight. In fact i'm using heavy for the diff and lightweight for th GB.

Just a thought, it might help better with the crunching. I noticed it improved the smootheness and eliminated the 1st to 2nd gearchange crunch/clunk.