Sr20 transmission questions

[Rocketbunny240sx]

Hey guys i got a 240sx s13 with hatchback and an sr20 i was just wondering what kinda transmission fluid i should put in. And would it matter which one i have to use if i have a racing clutch and an aftermarket flywheel or do i just use the same old tranny fliud? Also, how much hp can the stock tranny handle? Thanks guys

[Kingtal0n]

Redline MT-90


I've run them with regular random non synthetic gear oil before- it "works". But "they say" that it isn't good for the transmissions. And it might just be my imagination but the tranny seems to shift better with the MT-90 in it also.

As to holding power- think of this. Imagine you had only 100 horsepower and 100 foot pound of torque.

if I spun the engine to 6000rpm and dumped a twin plate clutch in front of a set of real slicks- it would probably only sustain one or two launches like that before the insides of the trans splatter everywhere. It is not so much about torque and power as it is applied resistance. I have used many stock sr trans with power levels around 400~ for years without problem by being gentle and not hooking up hard or using aggressive clutch discs.

[Rocketbunny240sx]

Ok cool. So wait should i or should i not run synthetic fliud? And yeah im running alittle over 400 hp so should i be concerned?

[TheRealSy90]

Ok cool. So wait should i or should i not run synthetic fliud? And yeah im running alittle over 400 hp so should i be concerned?

Redline MT-90 as was stated.


400hp is okay if you aren't using an aggressive clutch or launching the car on sticky tires or clutch kicking.


If you abuse it it's probably not going to hold up.

[Rocketbunny240sx]

i dont really go crazy on it but every now and then i do a pull on the highway

[jr_ss]

Don't be surprised to see a tranny grenade itself at any given time. I made a pull with my BPU SR on the street and my transmission gave up the ghost. I did frequent the drag strip during its lifetime. A simple upgrade is all you would need if it were to eat itself.

[Rocketbunny240sx]

Alright so what would you suggest upgrade? The gears? Or the whole tranny itself? I already have a act xextreme heavy duty clutch and a act alumunm flywheel.

[jr_ss]

You have to upgrade to a different trans. No need right now. Drive your car and enjoy it. Replace it when it grenades.

[1988montecarloss]

redline mt-90

[Rocketbunny240sx]

Ok cool thanks

[kruked]

Z32 trans.

[Rocketbunny240sx]

One more question. Say my tranny blew up now. What should i upgrade to?

[kruked]

Z32 trans.

(This is not a double post.)

[TheRealSy90]

One more question. Say my tranny blew up now. What should i upgrade to?

Z32 trans if you want 5 speed. Z33 trans if you want an even stronger transmission with 6 gears.

[Rocketbunny240sx]

Would you recommand a 6 speed tho? Like ive heard people say 5 is better then u hear 6 is better

[zenki_240sx]

I just bought this last night. Reading from all the threads, Amsoil seems to be the number 1 pick for everyone. I currently have Royal Purple on my tranny and J30 VSLD and its been about 2 years since I change it so I'm switching it up to Amsoil. Below is the link. First link is what Im using for my SR tranny and second link is for my J30 VSLD. There are a lot of great threads regarding which oil to use. Just have to read up on it.


http://www.amsoil.com/shop/by-product/transmission-fluid/manual/manual-transmission-and-transaxle-gear-lube-75w-90/?code=MTGQT-EA&utm_source=Email&utm_medium=OrderConfirm&utm_campaign=ProdSummary


http://www.amsoil.com/shop/by-product/gear-lube/synthetic-80w-90-gear-lube/?code=AGLQT-EA&utm_source=Email&utm_medium=OrderConfirm&utm_campaign=ProdSummary

[Rocketbunny240sx]

I know ive seen a few but it doesnt say anything about racing clutches and aftermarket flywheels i just wanted to know if i had a stage 3 race clutch would my tranny fluid have to be changed to something else or not

[zenki_240sx]

I have a ACT Street/Strip Clutch with a Fidanza flywheel. I had royal purple for about 2 years in the tranny and never gave me any issues. But I'm switching it out to Amsoil to try it out. I think since you have the tranny out, you might as well just change the oil so you don't have to worry about it later on.

[Rocketbunny240sx]

Yeah i figured which is why i asked everyone here for some tips and adivice xD

[TheRealSy90]

Would you recommand a 6 speed tho? Like ive heard people say 5 is better then u hear 6 is better


It's all up to you, neither one of them is really better when comparing the Z32 and the Z33 transmissions as far as outright strength. The Z33 six speed will retain almost the same top end speed as the oem sr20 5 speed, but you have an extra gear in between, so all the gears are shorter improving acceleration. The Z32 5 speed has taller gears and will have a slightly higher top end speed, sacrificing a bit of acceleration due to the longer gears. All of these changes can be supplemented with changing the differential gearing if you wish to, but it's not necessary.

I know ive seen a few but it doesnt say anything about racing clutches and aftermarket flywheels i just wanted to know if i had a stage 3 race clutch would my tranny fluid have to be changed to something else or not

Your flywheel and clutch have absolutely nothing to do with the transmission fluid! They do not interact with the fluid like a converter on an automatic transmission does.

[Rocketbunny240sx]

See this is why i asked xD thanks!

[TheRealSy90]

I'm sure that everybody was assuming that you knew that already.

[Rocketbunny240sx]

Sorry for being nooby im new to this 240 world, well to the transmission world to be exact didnt know alot about the tranny more about the sr20 engine itself

[Croustibat]

Ok cool. So wait should i or should i not run synthetic fliud? And yeah im running alittle over 400 hp so should i be concerned?

redline MT90. Yes it is not cheap, but it is nearly the only oil that will do the job.

If you really have 400HP the gearbox is going to break anyway. I go through a gearbox every 2 years, and that is with less than 300hp at the wheels. No hard launches, just some sticky tyres and a torsen, not even semi slicks. No clutch kick, no drift.

The 3rd gear usually dies first, it is in the wrong place. Torque kind of spaces the shafts, the 3rd gears are in the worst position for that, teeth get less and less overlap until they break. There is nothing to do but change the gearbox. Z33 is very good and strong, it will take whatever an sr20 can throw at it.

[Croustibat]

Would you recommand a 6 speed tho? Like ive heard people say 5 is better then u hear 6 is better

the S15 6 spd is crap. The 350Z 6 speed cannot be broken basicallly, and is shorter than the sr20 box except the 6th, which is nice both for cruising and on track. The gearbox itself is very smooth and precise. I know a couple of SR20 with one and an RB25 with one, all pro drifters, and breaking GB are now a thing of the past for them.

The problem with 300ZX Z32 gearbox is you will have a very hard time finding one in good condition... and it is slow and notchy compared to a Z33 one.