Since this has never been confirmed, becuase I am sure no one has actually done it, I have done the pleasure of doing it myself. This is a write up on the comparision of the RB25DET and VG30DETT transmissions and the swap itself.

First off here are the measurments of the two:

RB25DET:

Bell housing: 15 ½ inchesRear housing: 14 ¾ inchesShifter: 29 ¼ inches (from bell housing to middle of shifter).Middle case: 1 ¼ inches (where the bell housing and rear housing bolt onto).

VG30DETT

Bell housing: 16 inchesRear housing: 12 inchesShifter: 34 inches (from bell housing to middle of shifter).Middle case: 1 ¼ inches (where the bell housing and rear housing bolt onto).

Shifter position difference between the stock RB25DET and VG30DETT measured from the bell housing to the middle of the shifter hole is 4 ½ inches. VG being the longer one. ** keep in mind this is the RB25 bell housing on the VG transmission.

Driveshaft issues: Keep in mind for those that already have the RB25 in their car and have previously made the custom driveshaft to fit up to their original RB25 transmission and are now going with the VG transmission hybrid swap that you will have to modify the driveshaft since it is going to have to be about 2 ¼ inches shorter then the current driveshaft that you had made.

Now for those people that have said that even the bell housings will bolt up, that it 100% incorrect. They are different in many ways such as the starter natch out on the RB25 bell housing and the bolt holes themself are different.

The RB25DET bell housing will bolt straight up to the VG transmission without any problems. You can leave the rear VG caseing on, but like I had said above, the shifter itself will sit 4 1/2 inches farther back then the RB25 transmission. This wont be so bad for those with the stock R33 crossmember, since the shifter sits to far foward anyway. You are still going to hack up the transmission tunnel a little, but that just takes about 10 min.

For those that are asking why wouldn't you just get a RB25 transmission...well good luck finding one and when you do have fun spending the $1k plus. I bought my VG30DETT transmission for $150 with 30k miles on it and it takes about an hour to swap the bell housings around.

Hope this is a helpful write up....just figured it would be nice to have someone confirm it all.

thanks... i have been waiting for this.... nice that somebody had the part and the time to do this.... but the problem still ies in getting a rb25 bellhousing... or would a rb26 bellhousing be the same

ohh and by the way YOU DA MAN ...

I could not tell you if the 26 and 25 bell housing are the same. I know the front of the bell housings where it bolts up to the back of the block are the same, but for the bolt pattern being the same where it bolts up to the center section....it is likely.

Do you know of any parts that are compatable within the two?

For instance, are the flywheels the same and... i for one, if not broke somehow disconnected the shifter fork on my RB25DET transmission... but the thing is..... Im not sure its an RB25DET tranny out of an R33...the slave cylinder is actually like that of an SR20DET or KA24DE, the bolt holes are above and below each other rather than right next to each other on the top.

Example...

Here are three pictures of my transmission that came with my S1 RB25DET from venus auto. The speed sensor has been plugged for some odd reason and the slave cylinder venus sent me.. ALSO doesnt fit becuase it goes to a RB25DET tranny. Yet... my tranny still fit on my motor and drove fine untill... a few weeks ago when my car mysteriously stuck itself in third gear or any other gear thats foward even when its in neutral or REVERSE. The only time the car wont move foward is when the clutch is depressed other wise i can never move it backwards.





and with it installed using the stock KA crossmember and tophats mounts... it sits directly in the KA24DE shifter location.



Now i've had friends with the same setup and the shifter STILL sat foward, this is of course on RB20DET swaps..

I really dont mean to thread jack, but i find this discovery very important for me at the moment becuase if my shifter fork is broken then im kinda SOL finding a part for it.

good info DET.. im curious to see how you like driving with the shifter placed further back... not sure if id like that or not.. hell you could always create some linkage so that its in its stock location, ive seen it done an a sr20/s14 they hacked up the firewall and made the car a mid engine design, pretty sick stuff. the shifter sat way behind, with a little welding and custom fab the "shifter" was sitting right where it is stock.

Kansei240sx wrote:

sorry to say that your tranny in the picture is from a rb20det.

this is a rb25det transmission. notice the angle down shifter cover plate.

close up of the rb25det tranny

If i have an RB20DET transmission then how the hell did it bolt on to my RB25DET? And the fact that im using a 300zxtt yolk on the output shaft.

All the RB20DET trannys i've seen are way more slim than the one i have.

Yeah it's pretty big for a RB20DET trans. Maybe it's from aother nissan.



DET can't you just make the rails that attach the shifter longer like what Mozzy works dose on the there VG tran swap stuff?

There are two RB25 tranny's... the RB20DET/RB25DE tranny which was found mated to the RB20DET, but also to the RB25DE, and then there is the RB25DET exclusive tranny which wa only found on the RB25DET. The RB25 tranny's that you find for sale on ebay are probably RB20/RB25DE

here's the difference:

Yellow4g63 wrote:DET can't you just make the rails that attach the shifter longer like what Mozzy works dose on the there VG tran swap stuff?

thats exactly what i was talking about. all this tranny stuff makes me want to start reasearching how to mate a t56 up to a rb block. that would be the ultimate next to a 6 speed getrag.

Shocker wrote:
thats exactly what i was talking about. all this tranny stuff makes me want to start reasearching how to mate a t56 up to a rb block. that would be the ultimate next to a 6 speed getrag.

if i am not mistaken there is a company that makes an adapter to mount up a chevy trns to the rb....

I am not sure what you mean by making the rails longer. Are you talking about the fork that mounts the rear shifter?. The only thing that you could do is maybe cut the fork that mounts the shifter about an inch and a half shorter and then you would have to cut and then reweld the shift linkage connection as well...but to much work to save an inch and a half. You dont want to be making anything longer like I said it is already sits back about 4 1/2 inches farther back then the RB did with the stock R33 crossmember. There is nothing confusing about it....you take your original RB25 bell housing and swap it bolt it up and might have to cut the transmission tunnel shifter hole a little. With mine it already sat up to far, so really it is just going to be back a few inches. Even 3 inches back from the stock location isnt a problem....doesnt make anything uncomfortable.

There have been others that have had adapter plates to mount up domestic gearbox's, but have fun spending $1k just for the simple mounting plate. Need to remember if you plan on making 450hp+ with pretty much any domestic stock form gear box it isnt going to last you. You will have to get a drag setup transmission such as a powerglide and then you are racking up the cost to upwards of $1200+ for the transmission its and then having to purchase the adapter plate for the RB...then dont forget the torque converter which will run you $500+ for a decent one. It isnt cheap. For the Getrag setup....you are going to hack the living **** out of the transmission tunnel and make a new one. Going to have to disable the awd and have all that extra weight with the transfer case.

The VG30DETT/RB25 transmission can take a beating.....it has already been taken up to around 800h, so unless going all out drag car...why would you want to go through the effort of mounting up a heavier and more expensive transmission if you never plan on using it up to its potential?

Yea, I was about to say. That looked nothing like my S1 tranny.

But back on topic, excellent write up. I hope I never have to do a transmission repair, but if I do this will definately be the route Im going lol.

pirate87 wrote:There are two RB25 tranny's... the RB20DET/RB25DE tranny which was found mated to the RB20DET, but also to the RB25DE, and then there is the RB25DET exclusive tranny which wa only found on the RB25DET. The RB25 tranny's that you find for sale on ebay are probably RB20/RB25DE

here's the difference:

AWESOME! //sarcasm// so i have a mystery transmission..... There isnt anything RB20DET about my transmission...So it might be an N/A tranny. Im so confused on what to do right now.

Should i call venus and tell them that i've got the wrong thing? I mean... ffs i dont even have a speed sensor and the transmission didnt even last 5 months.

im pretty sure the supra getrag didnt come in AWD............ just a sticker price of at least 2500 for a used one. ha.

this is what im taking about.



notice the stud withought the shifter.. that is the actual shifter comming off the tranny. the one in front is the custom fabbed on thats basically just mounted to the top of the trans tunnel w/o the rear shifter it would just wobbel around freely.. basically just a simple extension of the real deal.

the car it is in. http://www.overboost.com/story.asp?id=1386

yeah the getrags alone are to much money coming out of a R34 GTR or Supra. Matters how unique one wants to be and also if they are shooting to be more of a track car rather then drag/street. If you are going drag/street I would recommend the stock RB25 or VG transmission for the cost or if you want to go all out then go with a powerglide or other domestic automatic transmission.

The idea of having another shift linkage is what I was originally thinking if I really wanted to go that route. It is always an idea, but I dont think it is going to be to much of a problem sitting right where it will be in the stock form sitting back a few inches.

DETurbine wrote:I am not sure what you mean by making the rails longer. Are you talking about the fork that mounts the rear shifter?. The only thing that you could do is maybe cut the fork that mounts the shifter about an inch and a half shorter and then you would have to cut and then reweld the shift linkage connection as well...but to much work to save an inch and a half. You dont want to be making anything longer like I said it is already sits back about 4 1/2 inches farther back then the RB did with the stock R33 crossmember. There is nothing confusing about it....you take your original RB25 bell housing and swap it bolt it up and might have to cut the transmission tunnel shifter hole a little. With mine it already sat up to far, so really it is just going to be back a few inches. Even 3 inches back from the stock location isnt a problem....doesnt make anything uncomfortable.

Yeah thats what I was thinking. They did somethng like that in a SCC mag for the VG engine swap into the 240sx. I'm not sure what month it was because I don't get them every month. So I would have to guess it was last months.

pirate87 wrote:There are two RB25 tranny's... the RB20DET/RB25DE tranny which was found mated to the RB20DET, but also to the RB25DE, and then there is the RB25DET exclusive tranny which wa only found on the RB25DET. The RB25 tranny's that you find for sale on ebay are probably RB20/RB25DE

here's the difference:

rb25 na manual tranny are the same as rb20. you're right, rb25det excluvisely have their own tranny, except the 4wd version.

Kansei240sx, your tranny may be a z32 hybrid. it it works, then might as well keep it, otherwise tell venus to replace it.

BoostsFed wrote:rb25 na manual tranny are the same as rb20. you're right, rb25det excluvisely have their own tranny, except the 4wd version.

Kansei240sx, your tranny may be a z32 hybrid. it it works, then might as well keep it, otherwise tell venus to replace it.

If i have a hybrid z32 transmission, which part of that would be z32? All i can think of is the bellhousing becuase i had to modify the starter plate for my starter by cutting part of it out to get my starter on.. but then again, that doesnt even make sense becuase appearantly the bellhousings are different size, and the fact that i dont have weird shift linkage parts to deal with on my tranny, the thing sits in my car and i drove it untill it broke.

ok has anybody tried putting the 300z bell housing on a rb25(or did i miss that some where).. it might take a little work but will it bolt up

DETurbine wrote:Since this has never been confirmed, becuase I am sure no one has actually done it, I have done the pleasure of doing it myself. This is a write up on the comparision of the RB25DET and VG30DETT transmissions and the swap itself.

First off here are the measurments of the two:

RB25DET:

Bell housing: 15 ½ inchesRear housing: 14 ¾ inchesShifter: 29 ¼ inches (from bell housing to middle of shifter).Middle case: 1 ¼ inches (where the bell housing and rear housing bolt onto).

VG30DETT

Bell housing: 16 inchesRear housing: 12 inchesShifter: 34 inches (from bell housing to middle of shifter).Middle case: 1 ¼ inches (where the bell housing and rear housing bolt onto).

Shifter position difference between the stock RB25DET and VG30DETT measured from the bell housing to the middle of the shifter hole is 4 ½ inches. VG being the longer one. ** keep in mind this is the RB25 bell housing on the VG transmission.

Driveshaft issues: Keep in mind for those that already have the RB25 in their car and have previously made the custom driveshaft to fit up to their original RB25 transmission and are now going with the VG transmission hybrid swap that you will have to modify the driveshaft since it is going to have to be about 2 ¼ inches shorter then the current driveshaft that you had made.

Now for those people that have said that even the bell housings will bolt up, that it 100% incorrect. They are different in many ways such as the starter natch out on the RB25 bell housing and the bolt holes themself are different.

The RB25DET bell housing will bolt straight up to the VG transmission without any problems. You can leave the rear VG caseing on, but like I had said above, the shifter itself will sit 4 1/2 inches farther back then the RB25 transmission. This wont be so bad for those with the stock R33 crossmember, since the shifter sits to far foward anyway. You are still going to hack up the transmission tunnel a little, but that just takes about 10 min.

For those that are asking why wouldn't you just get a RB25 transmission...well good luck finding one and when you do have fun spending the $1k plus. I bought my VG30DETT transmission for $150 with 30k miles on it and it takes about an hour to swap the bell housings around.

Hope this is a helpful write up....just figured it would be nice to have someone confirm it all.

hopefully that answers your question.

Does anybody have a part reference number list that i could post up and see if anyone can figure out what the fck my transmission REALLY goes to? Obviously the bellhousing CAN somewhat fit to an RB25DET becuase i drove on the sonbitch for 5 months before the shifter fork or collar on it dislocated itself or broke. I need to pull the tranny and post up the number on it.

well i just got my NEO RB25 and ithe tranny shifter is slanted on the one that came with my engine

Does it look like mine?

Also... the NEO tranny from my understanding is a pull type clutch.

The R34 RB25 is a pull type.

the only think i can think of regarding your tranny is that it might be some kind of rb25 z31 hybrid deal.

I highly doubt that.

The speed sensor shape and location is the same as an RB25DET and uses the 300zx speed sensor. Like all RB25DET and VG30DE/TT trannys do.

What might be going on is it might be a z32 n/a trans. The TT and N/A have the same transmissions but with a different bellhousing. The TT has a larger bellhousing (internally for sure). The TT has a larger flywheel. When doing the N/a to tt swaps, if you use the N/A trans you have to grind the bellhousing to fit the tt flywheel and shim the starter. I have never interchanged the tt and n/a transmissions and I know the bolt pattern is identical for the N/a and TT blocks (same engine verbatum minus pistons pretty much). So maybe that info helps. If anything everyone can find n/a transmissions too.

DustinZ