rb20 Transmission

[mannyvig]

I know this is prob the wrong place but I need an RB20 manual trans or manual trans bellhousing. Possibly i may need a clutch and flywheel for the 20. I know the RB25 trans is far superior to it but thats not in the "fun car" budget.

[Careless]

Manny, don't break the RB20 boxes. you'll end up exceeding the budget shortly. That's not "fun car"!

[AKWIKZ]

Manny,

I have a spare RB25det tranny sitting in the garage. It's not especially cheap, but I'm pretty reasonable. I could be open to partial trades as well. Let me know if you are interested.

 

 

Brian

[Kennysgreen280zt]

Glad to hear it got there brian!

[Careless]

Brian is excellent to do business with too, so jump on it if you can, Manny!

[mannyvig]

I have a few spare gtr parts or can go over and do yard work and house painting. let me know what you would like

[AKWIKZ]

Thanks for the plug. And kudos to Kenny on the tranny. You guys should really see the packing job he did on it. I have seen few, if any, people take that kind of care in shipping an item. If you still have my number Manny, give me a call and we'll see if we can work something out. I can tell you I am asking far less than these usually go for.

 

Brian

[Matt K]

BTW, if you blow up an RB20 tranny, you can use the guts from an SR or KA24DE tranny to replace the blown one, just have to switch the cases.

[mannyvig]

Thats why I will even just take the bellhousing. I have several KA transmissions sitting around even a fresh rebuilt one.

[Z U L8R]

i'm running rb20 transmission...

 

75W-140 SYNTHETIC MOBIL 1 FTW!!

[MrFancypants]

i'm running rb20 transmission...

 

75W-140 SYNTHETIC MOBIL 1 FTW!!

 

I'd be very careful with that. Make sure the RB20 tranny does not require GL-4, meaning Mobil 1 will toast your synchros because it is GL-5.

 

 

 

- Greg -

[Z U L8R]

if you run 75w-90 or 80s-90 which it calls for and you're hard on it, you're gonna mess up your tranny.

 

FROM MY EXPERIENCE on a shitty sr20 @ 14psi = 240rwhp/260rwtq, i went through 3 sr trannys . twice 5th gear synchro, and one second gear tooth broke. first tranny i used what it called for. second tranny i used redline mt 90, third one i said maybe it was just no good from the gate so i used mt 90 again. then finally i went with 75w-140 synthetic, i don't think it was mobil 1 i think it was motorcraft and never had a problem again.

 

i just finished a ka in an s14, i went cheap with gl-4 75w-90 and if you try to shift fast it's notchy, so i said ftw i put in mobil 1 75w-140, perfect shifts.

 

in my rb25 making the power it's making, i've been running the same rb20 tranny with 75w-140 mobil 1, still no problems, all synchros are perfect, i beat the hell out of my car (that's why i built it), and i'm sure the daul fingered OS Geiken super single is not very nice to my itty bitty rb20 tranny, but still......no issues.

 

the absolute ONLY thing i can say about 75w-140 is, in the winter for about the first 3-4 miles (when my tranny's cold) it's a little notchy getting it in gear. once it gets warmed up, perfect, no problems. that's it. if you're running 75 or 80w-90 in your tranny right now, and there's no problems with your tranny right now, i'd bet you'd feel an IMMEDIATE improvement in your shifting if you put in 75w-140 synthetic gear oil. just my .02

 

take it ez,

Dave

[MrFancypants]

Youre missing the point. It's not the weight, it's the GL rating. The synchros are not rated for Mobil 1 GL-5 gear oil. Use a proper GL-4 rated oil like Redline Heavy Shockproof or Royal Purple MaxGear.

 

 

 

- Greg -

[Z U L8R]

all the guys i know around here that ran shockproof killed there trannies within 3 months. that's why when i was searching for the lubrication solution i was asking around and seeing what ppl had the best luck with, so i ended up going with a 75w-140 synthetic. i hear what you're saying mrfancy, i'm pretty sure when i looked up z32 and 240sx manual tranny fluid type spec in alldata, i'm pretty sure it said to use a gl4 OR gl5, i can check tomorrow to be sure. not trying to start a huge debate, it's all in what has been tested, what works and what doesn't. so from my own experience i'll forever use 75w-140 in any nissan manual trans. that's just me. no hard feelings =]

 

EDITED:

hey i just checked alldata for a 93 240sx and 300zx and it says GL-4, but it also says "75w-90 recommended for ambient temperatures below 104 degrees F" and it gives a chart for temperatures and viscosity's. the chart does go to 75w-140 too. i'm not sure how exactly the ratings for gear lube go, however if it's anything like other tranny fluids, you know dextron 3 supercedes dextron 2, and a system calling for dextron 2 can use dextron 3, brake fluid calls for dot 3, but dot 4 is superior as it can handle more heat.

 

anywho, just going off experience alone, i've never broken a nissan tranny running 75w-140, and i know for a fact you'll feel the difference if you switch to it. now i need to do something about these s-rated tires >_<

[Careless]

how much weight is saved with the RB20 transmission in comparison to the RB25 FS530RA transmission?

 

Does anyone have the gear ratios of the RB20, and are they shorter? I Tried googling for a short while here at work, and I couldn't get anything. I think since the RB30 can handle 400 hp from ZUL8R's car, it should do well on the NA-RB30, and if it's got shorter gearing I think i'll make use of them, since they're way cheaper.

 

Problem would be clutch/flywheel, no? Or just clutch?

 

Found!:

Gear Ratios

1 3.321

2 1.902

3 1.308

4 1.000

5 0.759

Reverse 3.636

 

No designation of whether it's a FS5W71B or C, but I think all RB20's are B's

 

More info:

Fluid Capacity (recommended lubricant):

FS5W71C 5-speed Transmission: 4.25 qts (API GL-4, SAE 75W-90)

 

Gearing:

1st-3.985

2nd-2.246

3rd-1.415

4th-1.000

5th-0.821

Reverse-3.657

 

Nissan recommends 90W GL-4 gear oil for this transmission. GL-5 gear oils which are required in hypoid differentials are not used in most synchromesh transmissions. The chemicals used in the GL-5 oil that provides the extreme pressure protection can be corrosive to synchronizers, which are commonly made of brass or bronze. Typically, the use of a GL-5 lubricant in a synchromesh transmission will shorten the synchronizer life by one half.

[MrFancypants]

The chemicals used in the GL-5 oil that provides the extreme pressure protection can be corrosive to synchronizers, which are commonly made of brass or bronze. Typically, the use of a GL-5 lubricant in a synchromesh transmission will shorten the synchronizer life by one half.

 

Ah - that was helpful

 

Having personally disassembled several FWD SR trannies, I can say they use brass baulk rings on their synchros. Not 100% sure of the same for RB20 transmissions, but I dont think it is a stretch to assume so. Based on the GL-4 spec I think youre a gambling man if you put Mobil 1 gear oil in a RB20 transmission.

 

 

 

- Greg -

[Z U L8R]

wewt! =]

 

i opted to go with the rb20 tranny for a couple reasons.

 

*i'm using the stock l28 driveshaft*

*my speedo works*

 

*i'm using the stock l28 tranny mount (i had to cut the center section and move it 1.5" then reweld it back together*

*i have the 25 tranny if i ever go 26 or if i wanna sell it i can* (it's sold now)

 

it was just easier for me and more cost effective to go with the 20 tranny. i'm pretty sure i have motorcraft 75w-140 in it atm, not mobil 1, not sure if that makes a huge difference but i wouldn't feel bad using mobil 1 either and i have used mobil 1 on other cars that haven't had an issue yet either. i appreciate the information from both of you really i do. and seriously i'm hard on my car as in leadfoot, not maintenence. maintenence-wise i'm the most anal person ever, i've already changed my plugs 6 times since march at least, with ngk 5690's 7$/per plug, i change my oil at the end of every month, etc etc. i'm running an OS Geiken super single 6 puck unsprung clutch & flywheel for an rb25 (so no worries on what clutch or flywheel to use), my friend is the opposite, he's running his rb25 tranny and clutch on a stock rb20 engine LOL. but anyways, again i really appreciate both of you. if i kill my tranny i will make a post to show the destruction =] speaking of which i've got 700 miles on my new bottom end (wiseco's 20 over, stock rods, acl bearings, new oe oil pump, n1 water pump) and hopefully this weekend i can get it tuned, i'm hoping to make ~480rwhp/400rwtq @ 23-24psi, but i'm going for the gusto and gonna try to max out the 30/71 LOL

 

30psi 530rwhp.....riiiiight, anywho, take it ez fellas, i'll let ya know how it goes, thx again

Dave =]

[Careless]

I hope the transmission serves you well!

You say that it can use the stock L28 drive-shaft too? I'm using an S14 rear sub-frame, so I'd have to see if it would still line up, but... here's to hoping that it works out! *high 5*

 

I'd bet there's a 20 - 50 lbs weight savings on the RB20 transmission as well. I might just opt out and go for that then, since I'm sure they're cheap as hell too

 

are the clutch and flywheel the same though? hmmm..

 

EDIT: looks like RB20's use the same flywheel and clutch as the RB25, seeing as the JGY parts are compatible on both transmission/engine combos. looks like RB20 transmission for me. Just saved me 600 dollars. And the worst part is... now I can't decide what to spend it on.

 

Actually, i'll just buy the clutch and flywheel with that cash. Getting a complete transmission package for the price of a transmission that is more powerful than I really need- without clutch and flywheel is a better way of doing it the first time around in this case.

[Careless]

Guys, since we're on the subject of RB20 transmissions and KA/SR transmissions, here's a good rebuild thread.

 

Looks pretty fun to do, and could mean the difference between yummy synchro shavings, or even yummier seat time in a car that actually moves =)

 

http://forums.nicoclub.com/zerothread/239220

[mannyvig]

Ok most likely going to go with brians 25 trans. As far as the clutch and flywheel are concerned:

The Spec carbon-kevlar stage2+ clutch will prob be the one on order but not to sure about the flywheel. Exedy has a decent reputation and they have a semi decent al one for around $350. Not sure how much i would trust that. (We all saw the pics of a wheel goung through the hood). Anyone have a decent wheel to bolt to an rb20. Or does anyone have opinions on the matter.