RB25 Trans Mated to Z32 Trans - Lots of pics, explanations...

Discuss the RB20, RB25 and RB26 series engines.
Booztd 3
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RB25 Trans Mated to Z32 Trans - Lots of pics, explanations...

Postby Booztd 3 » Thu Feb 08, 2007 8:47 am



Guys

First off, I would like to preface this with a warning. THIS IS NOT FOR THE AVERAGE MECHANIC. Hell I wouldnt even recommend this for the skilled mechanic. I consulted my older brother who owns a speed shop in springfield IL named FC Customs (www.fccustoms.com) to help with the work. This work is being done because I am swapping an RB26DETT into my Z32. More info can be found at my website http://www.rbz32.com

Over the last two nights we broke down the Z32 Tranny, as well as the RB25 RWD Tranny. We then mated them together following Charlie C's suggestion that the input shaft needed to be swapped to compensate for bell housing lenght.

I will also re-preface this write-up by warning you almost every picture contains the 'shocker' LOL. We were feeling goofy during the process, so why not spice up the pics a little bit?

Here we have the Z32 Trans



You will begin by pulling the outter detent ball out of the trans. On the upper side close to where my bro's index finger is pointed in the picture above. Remove the 17mm bolt on the left hand side and remove the spring and then remove the ball. Keep these in a safe place.

Now you'll remove the front cover like so



Front Cover removed



Now you'll need a few different sets of snap-ring pliars. There is one small snap-ring and washer and a large snap-ring once you get the front cover off



Snap Rings





Now We'll work on the shifter rod. Begin by pulling the 10mm bolts out and pull the cover off. You'll see this



There are two dowel pins you need to remove in order to get the shifter rod out.

Now we'll remove the bell housing by removing the casing bolts in the middle of the trans. You'll need a hammer to separate the two pieces.



A close-up of the gear-set



Our next part is a highly debated topic regarding Z32 and RB trannies. The 4th gear synchros DONT grind, its actually the insert springs. You can see in the next few pics how the teeth have been ground and dulled down





Now you'll remove the forks from the gear-set





After you've removed the shifter rod and the pieces inside the trans, you can now remove the tail section casing





Here is another component that causes the grinding



Notice the teeth are worn down



Now this is where things get hairy. You're going to need the bomb-diggity puller set in order to get everything off the right way. We accomplished this witha $2500 Set from Snap-On



Gears starting to come off



Using the pinch puller for the lower bearing





We had to craft this next setup out of threaded rod and one of the pullers. It worked at least!



After removing the other gear above with the pullers, the remaining gears should come off with some prying/tapping of a hammer. Now the directions call for pressing the shafts out of the center-section. We did this using a press. Since the shafts are still bound together by the gears, you must press the shafts out one bit at a time, and then switch to the other shaft and press it out a bit. This makes is so the shafts dont bind.



This is how we felt at the end of night 1



Moving on to day two, we have an RB25 RWD Trans



I'm not going to go through the dissasembly process, because its quite identical to the process of removing the front/rear casings.

Here we have the Z32 Input/Output Shaft on the top, and the RB25 Input/Output Shaft on the bottom



Here are some comparison pictures of the bell housings





My stuff was pretty dirty and my bro's shop just had gotten a new parts washer in. This thing RULES. I give you ......"The Cuda"



Parts going in



Here's how the bell housing turned out



Center Section





Here the RB25 trans gearset.



Since I wont be needing alot of extra parts, we opted to cut the countershaft out with a plasma cutter, and avoid a crap-ton of parts removal.









Now since the input shaft isnt bound by the counter shaft, it slides right out



The mess we made



Now we're finally on to the reassembly process. We heated the parts on that usually get pressed on. We just put them in the parts washer for a few minutes and they went on pretty easy with a hammer. We used alot of the insert springs and such from the RB25 trans since they were in alot better shape than my Z32 trans. It basically ended up taking all the good parts from both and combining them.



Everything into place, forks are back on





Snap-Rings going back on



Front Cover sealed up



My brother on the right and tony (stallone) on the left. These guys were a huge help and I couldnt have done it withouth them



The completed RB25/Z32 Trans





Now onto some notes:

When I first read what needed to be done to the RB25 and Z32 trans it made a lot of sense, having to use a different input shaft to compensate for bell housing length, but the way I understood it was that the RB25 bell housing was longer, thus making the input shaft longer as well. If you read through this how-to, you’l definitely see that the bell housing is actually shorter. So in theory if we just switched the bell housings, the input shaft would be too long on the transmission, but this really isn’t the case. We measured the input shaft length, and theres only 1/8” different between input shafts. It is more than likely this 1/8” would be negligible when installing the transmission, considering the input shaft does not even fully seat on the pilot bushing. Even if you did run into that issue, you should be able to cut off the excess 1/8” from the Z32 input shaft.

Here is also a picture of the puller kit we used



Some pics of the shop and the cars

Panoz GTS on the dyno and STS C5



My bro's mid 10-sec stock block/stock head/stock cam 05 mustang





Their Ford GT



Blower & AFR Head setup going on an escalade





Arial View



Peace!


Yellow4g63
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Re: RB25 Trans Mated to Z32 Trans - Lots of pics, explanations... (Booztd 3)

Postby Yellow4g63 » Thu Feb 08, 2007 9:14 am

Very nice write up on the Z32 to RB trans. Even nicer shop!

Booztd 3
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Re: RB25 Trans Mated to Z32 Trans - Lots of pics, explanations... (Yellow4g63)

Postby Booztd 3 » Thu Feb 08, 2007 9:33 am

Yellow4g63 wrote:Very nice write up on the Z32 to RB trans. Even nicer shop!
Thanks a bunch

BTW how much does one of those RIPS intake manifolds go for?

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Re: RB25 Trans Mated to Z32 Trans - Lots of pics, explanations... (Booztd 3)

Postby Yellow4g63 » Thu Feb 08, 2007 9:37 am

Booztd 3 wrote:
Thanks a bunch

BTW how much does one of those RIPS intake manifolds go for?
lets just say I'm still crying I think it was 1200-1300 shipped for the kit.

Booztd 3
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Re: RB25 Trans Mated to Z32 Trans - Lots of pics, explanations... (Yellow4g63)

Postby Booztd 3 » Thu Feb 08, 2007 10:08 am

Does that kit include the throttle body? If so thats not too shabby

I just paid out over 2grand for my exhaust manifold

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Joe
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Re: RB25 Trans Mated to Z32 Trans - Lots of pics, explanations... (Booztd 3)

Postby Joe » Thu Feb 08, 2007 10:25 am

WOW! thats one hell of a write up man!! thank you!

So, after being a part of this, would you say a Z32 gearset would fit inside a RB25 transmission case?

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Re: RB25 Trans Mated to Z32 Trans - Lots of pics, explanations... (Booztd 3)

Postby Yellow4g63 » Thu Feb 08, 2007 10:32 am

Booztd 3 wrote:Does that kit include the throttle body? If so thats not too shabby

I just paid out over 2grand for my exhaust manifold


Yup it did, even came with a intakemanifold gasket and a new Tstat housing so the manifold clears. I did the intakemanifold swap with the motor in the car.

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Re: RB25 Trans Mated to Z32 Trans - Lots of pics, explanations... (Kamin)

Postby Booztd 3 » Thu Feb 08, 2007 1:09 pm

Kamin wrote:WOW! thats one hell of a write up man!! thank you!

So, after being a part of this, would you say a Z32 gearset would fit inside a RB25 transmission case?
No, it wouldnt. If you look at the picture of the input/output shafts sitting side by side, you'll see that the rb unit is much longer in total lenght. Also if you look at where the shifter is layed out, its a completely diffrent setup. The shifter on the RB comes directly out of the casing, whereas the shifter on the Z32 has a rod that protrudes from the rear of the casing, and then has a tail section attached to it.

The gears/synchros are completely interchangeable however

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Postby gawdzilla » Thu Feb 08, 2007 1:44 pm

could you have done this with the z32 rear housing and the rb26 front housing and saved yourself from buying a rb25 transmission?

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Postby Darius » Thu Feb 08, 2007 1:44 pm

This is the single most thorough write-up on anything I've seen this side of the Mississippi. Kamin, this is destined to be a STICKY some day:bigthumb

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Re: (gawdzilla)

Postby Booztd 3 » Thu Feb 08, 2007 1:50 pm

gawdzilla wrote:could you have done this with the z32 rear housing and the rb26 front housing and saved yourself from buying a rb25 transmission?
I *probably* could have, however I KNOW that the rb25 housing definately works, and at the time I didnt have an rb26 tranny to compare to, and also, I wouldnt have been able to 'rebuild' my transmission with all good parts, since the rb26 trans is totally different.

I realize I could have taken apart the RB26 trans, used the bell housing, sourced another good z32 trans for synchros/gears, etc etc but by the time I bought my RB tranny, and I have the rb26 trans sold for 400, I have probably the same amount of money/energy involved.

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Re: (Darius)

Postby Booztd 3 » Thu Feb 08, 2007 1:52 pm

Darius wrote:This is the single most thorough write-up on anything I've seen this side of the Mississippi. Kamin, this is destined to be a STICKY some day:bigthumb
Haha thanks man, just wait until I do the official write-up for the RB26 into 300ZX

I usually make a habit of doing write-ups when I can. I know how much it pisses me off when I try to find info on something and I can never find what im looking for. I know that guys will appreciate this when they need similar info, and its all right here.

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Re: (Booztd 3)

Postby REDLN » Thu Feb 08, 2007 3:30 pm

nice write up honestly. thanks for doing this i needed it for mine that i'm currently working on. but i don't have all the tools you have at you dispense. this should be a sticky.

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Spazz
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Re: (REDLN)

Postby Spazz » Thu Feb 08, 2007 3:41 pm

+1 for sticky material, this kinda info doesnt come around very often.

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Re: (REDLN)

Postby 240z4u » Thu Feb 08, 2007 3:46 pm

Whatsup man, nice writeup. I used a z31 turbo trans behind my rb25det with an rb26 awd bellhousing.

I am currently trying to get my employer to transfer me to peoria, maybe ill see you around sometime.

Evan

BTW, nice shop.

Booztd 3
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Re: (240z4u)

Postby Booztd 3 » Thu Feb 08, 2007 4:12 pm

240z4u wrote:Whatsup man, nice writeup. I used a z31 turbo trans behind my rb25det with an rb26 awd bellhousing.

I am currently trying to get my employer to transfer me to peoria, maybe ill see you around sometime.

Evan

BTW, nice shop.
Nice! Good luck!

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Shocker
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Re: (Booztd 3)

Postby Shocker » Thu Feb 08, 2007 4:53 pm

awesome man.. so your telling me.. If say my rb25 trans starts to wear.. as in syncros are going grinding gears, my local tranny shop should have no problems swapping in z32 gears and syncros for a full rebuild.. thus saving the whole hassell of replacing the whole entire tranny?

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Re: (Shocker)

Postby Booztd 3 » Thu Feb 08, 2007 6:48 pm

Shocker wrote:awesome man.. so your telling me.. If say my rb25 trans starts to wear.. as in syncros are going grinding gears, my local tranny shop should have no problems swapping in z32 gears and syncros for a full rebuild.. thus saving the whole hassell of replacing the whole entire tranny?
Absolutely. The 'guts' of the two trannies are identical. Its just the lenght of the input/output shafts, shifter layout, and bell housing layout that separate the two

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Chaos the Xile
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Re: (Booztd 3)

Postby Chaos the Xile » Thu Feb 08, 2007 7:19 pm

+1 for sticky,this is the greatest write-up as Darius said. Info was soild explainations were extensive yet understandable! Great work! Now I know the Z32 and RB25 synchros are interchangable! Great solid info man!

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HxC_Nismo
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Re: (Chaos the Xile)

Postby HxC_Nismo » Sun Sep 23, 2007 9:27 am

good write up also the rb25det and rb26dett shifts forks, synchroes and gears sets are indentical except for the output shat is shorter on the rb26 and also the shifter rod is longer on the rb26 compared to the rb25. ill put a pic of the 26 and 25 gears sets next to each other so you can see and compare for yourself.

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Abdo
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Re: (HxC_Nismo)

Postby Abdo » Mon Sep 24, 2007 1:10 pm

good work, great info, excellent writeup!+1 for stickies.

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Re: (Abdo)

Postby Kalypso » Sun Nov 02, 2008 5:41 pm

STICKY!

so after all this, you've taught us that swapping the bell housings is acceptable.

there still one basic things that I missed, you did this primarily because you wanted to still use your z32 transmission at its stock shifter position with rb25 internals?



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