The stronger one, 4- or 5-speed?

[Suomizeta]

I broke my gearbox, 5-speed. Lots of used 4-spd for sale around here, (northern Europe) but very few 5-spds. My 240z has an L28et engine, so the transmission should be BW T5 like in 280zx turbo.. But we don't have many of  those here...

The question is: is there a difference in the strenght between Datsun original 4- and 5-speed transmissions?

And: I believe that many who have tuned up their 240z engines have still the original tranny, not something stronger like BW or ZF (from BMW or  else)?

How much torque do Datsun 240Z transmissions handle? 

[cgsheen1]

1 hour ago, Suomizeta said:

The question is: is there a difference in the strenght between Datsun original 4- and 5-speed transmissions?

I doubt there is, the early 5-speed uses the same basic parts as the 4-speed and adds an overdrive gear. I've used a late 280ZX close-ratio Nissan 5-speed behind my L28ET for several years but I'm relatively easy on it... I also have a T-5. Want me to ship it to you?

[Zed Head]

3 hours ago, Suomizeta said:

I broke my gearbox, 5-speed.

What broke?  That might be a clue to how a 4 speed will do.

You could use the front case/bellhousing from your 5 speed to convert a 240SX 71C 5 speed.  Wider/stronger gears and bigger countershaft bearing on the later models.

[Suomizeta]

Lost some teeth from gear 3. Two of them came out with the oil. It was an old and worn box.

I'm not very much into modifications and changes, but probably gearboxes from naturally aspirated Datsuns won't last very long with added turbopower? 

 

[zeeboost]

I’ve gone through 3 datsun 5spd transmissions in my 240z l28et, but it’s modified. The next trans will be one from a z32, but I’m not sure if those adapter kits are still available. Pretty sure the thing now is to mate a 350z 6spd to it, but I havent done any research on that swap.

 

Last I checked, parts are still readily available for the T5 trans, but im not sure if the 280zx T5 uses the same internals as say a foxbody mustang T5. A rebuild kit is more than likely just seals, synchros and bearings, but you may still be able to find replacement gears for yours. If you’re running a stock L28et then a stock T5 should be fine, as thats what they were rated for.

But to answer your question, I’ve seen those 4speeds take quite a bit of abuse and keep ticking, so if you’re in a pinch and you can get one cheap, it should work fine. 

 

[Zed Head]

Here's more detail on the 240SX option.  Many people have done it.  It's fairly simple.

http://atlanticz.ca/zclub/techtips/240sxtransmissioninstall/index.html

http://zhome.com/ZCMnL/tech/240SX5spd/transmission.htm

[Suomizeta]

Here in my country they are 200sx, not 240sx. Maybe they still have the same tranny? How do I find the best S30 fitting SX gearbox type? With a code maybe?. 

[jonbill]

UK/European S13 and S14 200sx have Fs5w71c gearboxes too.

[EuroDat]

18 hours ago, jonbill said:

UK/European S13 and S14 200sx have Fs5w71c gearboxes too.

Yes, but they don't have the heavy duty 240SX transmission with the 20mm gears and synchro reverse gear. The 200SX uses more or less the same as the 300ZX with the 16mm gears.

IIRC the 200SX has a strange selector set-up. It's been a while since I saw the internals of one.

You can transfer the FS5W71B front casing to any of the 71C transmissions. It's a fairly easy mod to do and they are easier to find than a T5 with an L28 bolt pattern.

Edited September 14, 2019 by EuroDat

[jonbill]

Yes, but they don't have the heavy duty 240SX transmission with the 20mm gears and synchro reverse gear. The 200SX uses more or less the same as the 300ZX with the 16mm gears.
IIRC the 200SX has a strange selector set-up. It's been a while since I saw the internals of one.
You can transfer the FS5W71B front casing to any of the 71C transmissions. It's a fairly easy mod to do and they are easier to find than a T5 with an L28 bolt pattern.

I believe you - certainly mine doesn't have synchro on reverse but I haven't found the gear selector strange at all, in fact that's one of its best bits in that it came with a nice quick shift kit.
It's been plenty strong enough for me, but I'm not into turbos. I believe them to be good for circa 350-400bhp.

[EuroDat]

The problem with the 71C transmission is there are so many variants. I have heard up to 12, and that is not the ratios. I have two and they are different lengths.

I am on holiday and don't have much on my tablet, but here is a quick example of stuff I have found over the years.

The stuby rear extension has a different selector rod linkage. The external selector is exactly the same as the 300ZX. I know the for sure.

Comparing the FS5W71B.pdf

[Zed Head]

I had a thread over on Hybridz about the variations and there are a bunch, with reverse synchro and double synchros on some gears, along with the different ratios and wider gears .  And they're not all called 71C, they go all the way up to 71H.  The truck variations might have the wider gears, outside of where the 240SX was sold.

When nicoclub had all of the Nissan manuals online you could browse through them and see the differences.  Nissan got all snooty and claimed copyright, forcing them to remove them from the site.