Zman0690 Posted January 21, 2007 Share Posted January 21, 2007 Well I've searched and I can't seem to find any info on this, just some people making some assumptions about its limits and deciding to go automatic or another route. So does anyone have any difinitive HP or Torque limits of this transmission? Or is this a mute point as I have heard more about stub axle/companion flange/CV failure than the transmission failing? As a side note anyone know what some of these 1000hp Jun, top secret, hks cars are doing to confront these problems, and yes I know they are AWD cars thus their will be a torque split. So did I answer my own question? Quote Link to comment Share on other sites More sharing options...
alexideways Posted January 21, 2007 Share Posted January 21, 2007 Well, the RB25 tranny is the same as the Z32 ( check this statement for trueness, it's what I read.) so, you might check into these and might find more info. good luck. Quote Link to comment Share on other sites More sharing options...
Zman0690 Posted January 21, 2007 Author Share Posted January 21, 2007 While taking alex's advise I found the following on rbmotoring.com, although it does not state limits I think it gives an idea. Transmission - In R32 ,R33 making over 500hp to the rear wheels , 3rd gear has had some issues while drag racing. The synchros are also not all that durable. The internals of the R32,R33 are the same as the 300ZX twin turbo. Redline Shockproof Heavy Gear Oil. We used it in our 10.7 drag car with a stock transmission and it seems to really help with transmission durability. The Getrag in an R34 requires its own special oil.The oil is available from Toyota dealerships and its $40 a liter. The Getrag does not like Shockproof Heavy, so don't use it in it.. OS Giken transmission internal upgrades for the R32-R33 seem to be good up to 700 hp. So anyone out there hit their 600hp mark using a RB25 transmission? If so what is your experience? 1 Quote Link to comment Share on other sites More sharing options...
alexideways Posted January 21, 2007 Share Posted January 21, 2007 Thanks, good info. Quote Link to comment Share on other sites More sharing options...
Ripper Posted January 21, 2007 Share Posted January 21, 2007 The Rb25det- R33 gearbox is different to both the rb20det- r32 and Z32 gearbox. It is a strong box when treated with care like stated above. It is much stronger than the R32 box. I speak from experience. The synchros in all 3 of these boxes are the weakest link. However I believe the r33 gearbox has the strongest gearset. Quote Link to comment Share on other sites More sharing options...
rb26zed Posted January 21, 2007 Share Posted January 21, 2007 The Rb25det- R33 gearbox is different to both the rb20det- r32 and Z32 gearbox. The RB25DET/R33, Z32, R32GTR and R33 GTR Gearbox internals are identical. R34 5 speed box's will be the same aswell. The simillarities between these boxes are as a whole gearset as there may be some minor differences with ratios and synchros. Strength wise they are the same. R32/RB20DET are different they are the same as SR20 and CA18 boxes. Quote Link to comment Share on other sites More sharing options...
hotimport Posted January 21, 2007 Share Posted January 21, 2007 This is actually very intresting to me, you guy saying that the R32, R33 and R34 gearbox is are diffrent? And Ripper from AU is saying that the R33 tranny is by far the strongest. Wel I dont really agree with that. The R33 tranny has the strongest synchros that is probably true but as far is gearing and everythig eles goes its the same and the bellhousing too because it plays a big roll in substantial to the engine in transforming the power. I have a an R34 RWD tranny that seems to have a better stronger bellhousing then the other 2 and stronger gear set, but there all the same component built. Just like the quote from RB motoring site said, it will most likelly last to about 600-700 HP just like quoted below. Anythig more powerful then that would needs to be rebuild to with stand high HP numbers. "quote" The Getrag in an R34 requires its own special oil.The oil is available from Toyota dealerships and its $40 a liter. The Getrag does not like Shockproof Heavy, so don't use it in it.. OS Giken transmission internal upgrades for the R32-R33 seem to be good up to 700 hp. My biggest concern with these trannys is you can push high numbers but unless you would really drag youre car you dont have to worry much about it. But when something brakes do you really want to rebuild the tranny or replace it with for example the stronger TH350 tranny or something in that nature, and the other thing is how long will it hold until you have to totally rebuild it? Quote Link to comment Share on other sites More sharing options...
Zman0690 Posted January 21, 2007 Author Share Posted January 21, 2007 This is indeed why I posted this in the first place. My Hp goal is around 600 or mid 10s in my 240z in the quarter, whichever comes first. I do not wish to invest in this setup ( Flywheel, clutch, Trans, crossmember, driveshaft, etc. ) and then have to swap it completely out and start all over. How long will these transmissions last? If their internals are the same as the Z32 then does anyone know of an upgraded syncro/gear setup that would work? Kind of odd that there is no one on here that has pushed these transmissions to their limit, none that I could find anyway. Quote Link to comment Share on other sites More sharing options...
hotimport Posted January 21, 2007 Share Posted January 21, 2007 How long will these transmissions last? If their internals are the same as the Z32 then does anyone know of an upgraded syncro/gear setup that would work? Kind of odd that there is no one on here that has pushed these transmissions to their limit, none that I could find anyway. Well i see what you saying and to be honest with you there is people on this forum that have pushed their trannys and RB motors to its limits. Its just not clear to me when it will aproximatelly give out and what will give out. These trannys are pretty strong and you need alot of balls and power to totally brake them. This is just an example of a guy here " His car dynoed and high 500 hp that you drive around allmost every other day and have no problems in the driveline. Now you take the car to the track once in awhile and it performs well with no problems and runs low 11's. Here is the other senario, you take the car to the drag strip to race that you have build only for a drag strip where bad things happened to the tranny like miss shifts, gear grinding and etc... In these 2 cases its most likelly to happen to the car that gets alot of abuse on the track." The guy that took his car to the limits his name J Taylor found him self with a smoking piston after he raced a Viper but hes tranny was absolutelly fine as far as i know. And thats with an RB25 with stock internals. Now as you mention before that people brake everything eles on chassis before they brake their tranny. Thats just simply because the tranny will need to be beaten so hard on before something will happen to it then the driveline componets. Because the RB motor class is a tough cockie to brake that easilly. On the rebuilding end i beleive that OS Giken makes some quality parts to rebuild these RB tranys or the other choice would be to just swap out for unbrakebale tranny like TH350 for extreme choice of power and abuse. Just my .02 cents on these tought. Quote Link to comment Share on other sites More sharing options...
stony Posted January 21, 2007 Share Posted January 21, 2007 For the street the tranny is fine for a while but hard shifts will kill the scyncros eventually. The reason most of the people have gone to autos that run at the track is because they want to go faster and be more reliable. The rb25 tranny is strong but it is stock. you will spend way more money on upgrading the 5 speed to be realiable then just going to an auto. I went to a 2 speed. Total cost of going to a "good" 2 speed setup ( tranny, torque converter, adaper kit) for me was around 5K. You cant touch a "good" upgraded 5 speed that will hold 600+ for even close to that. Then you still have to go out and get a clutch. just my 2 cents. Quote Link to comment Share on other sites More sharing options...
Booztd 3 Posted January 21, 2007 Share Posted January 21, 2007 You guys need to understand that is is NOT the sunchros that fail. I have dissected several of these transmissions, and it is actually the insert springs. These are the pieces that actually apply pressure to the synchro which then speeds it up to the speed of the gear. These insert springs fail and that removes the process of speeding up the synchro. Here is a picture of what the assembly looks like Quote Link to comment Share on other sites More sharing options...
Zman0690 Posted January 22, 2007 Author Share Posted January 22, 2007 I can't seem to get your link to work, please repost. Quote Link to comment Share on other sites More sharing options...
MrFancypants Posted January 22, 2007 Share Posted January 22, 2007 Havent seen the guts of a RWD Nissan tranny, but sounds like they have the same Achilles heel as their FWD tranny (3rd gear). On the FWD, it's 3rd gear on the input shaft that fails (strips teeth). Cryotreating, shotpeening, etc. will help make the shaft stronger, but ultimately the cause of the problem is case flex. The case flexes such that the input and main gears do not mesh perfectly (they spread apart), and then teeth shear off. Try taking off the bell housing and reinforcing it with pourable metal epoxy (McMaster Carr). - Greg - Quote Link to comment Share on other sites More sharing options...
Booztd 3 Posted January 22, 2007 Share Posted January 22, 2007 Here is the picture re-hosted 1 Quote Link to comment Share on other sites More sharing options...
nashz32tt Posted January 22, 2007 Share Posted January 22, 2007 i would have to agree with booztd 3. That is what caused my tranny failure last year. I could not do a fast shift from 1st to 2nd - just would not engage. anyway, I got it home and drained the fluid the next day and on the end of the magnetic bolt were about 4 of these springs. When I tore it down, i found about 5 more springs in the bottom of the case. This is actually what prompted me to go ahead and do the RB26 swap into my z32. BTW, i ran a 7.13 @ 86.03 MPH in the 1/8th this past Saturday. Not bad for stock set up and M/T et streets. David Quote Link to comment Share on other sites More sharing options...
alexideways Posted January 22, 2007 Share Posted January 22, 2007 Are there some better components, that could replace those springs, out there??? Quote Link to comment Share on other sites More sharing options...
nashz32tt Posted January 23, 2007 Share Posted January 23, 2007 that's a good question Alex, b/c i still have a good set of guts sitting in my garage. Maybe there are better synchros for these trannies. I just have not thought about searching for them. Might search for them at work tomorrow - need something to do anyways - hehe Quote Link to comment Share on other sites More sharing options...
alexideways Posted January 23, 2007 Share Posted January 23, 2007 Well, keep us posted then. Thanks. Quote Link to comment Share on other sites More sharing options...
Zman0690 Posted January 23, 2007 Author Share Posted January 23, 2007 Nashz32tt you state that your tranny failure is what prompted you to do the RB26 swap but you did not state what tranny you ended up using in your swap. I thought it was established earlier in this thread that the R32/33 had the same internals as the Z32. So did you end up using a 5spd out of a r34? Preliminary searching has not produced any upgrades for the Z32 tranny but I'm still looking. Also several other sources I've found have also stated the HP limit of the Z32 at around 600hp. Quote Link to comment Share on other sites More sharing options...
nashz32tt Posted January 23, 2007 Share Posted January 23, 2007 Sorry about that, i posted elsewhere about my swap. It is the rb25det tranny. I am using the z32 tailpiece on the rb25 tranny. As for the internals, I set them side by side and counted the teeth on each gear. they are the same. I am using the speedo sensor from my z32 and the mph is dead on. the rb25 main shaft is almost 3" longer at the rear of the tranny. I had to put the z32 shifter rod into the rb25 tranny so that the z32 tail piece would fit on it. Quote Link to comment Share on other sites More sharing options...
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