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***EDIT***
If any of this information is found to be in error, please let us know so it can be corrected.
Summary:
The Z31's 71C transmission is virtually identical to the 240SX transmission. Considering the S13 transmissions can be found dirt cheap, it's often times a better and/or cheaper option to buy one and swap the bellhousing/front case as opposed to buying a used Z31 71C transmission.
You can swap just the Z31 71C bell housing onto the SX trans or the entire gear cluster (with shift forks) into your full Z31 case. Either way, the gear clusters usually have to be swapped in their entirety as there are subtle differences in gears, ratios, shift forks, roll pins and their locations on the shift rails. People have gotten into that and compared, but it's a big bag of worms with the small differences in the SX transmissions.
The 240SX case has a different rear seal, speed sensor (electronic) and/or speedo pinion. The shift lever is slightly different, but the top plate is the same. The gear position sensors are the same (simple contact switch), but have different connectors.
FYI: These transmissions are well known for broken shift forks. Some of the later versions partially corrected this issue due to different designs.
***Orig. post below***
We have long known that you can swap the front half of the case Z31 71C manual transmission onto a 240SX 71C manual transmission and use it in your Z31. The question I have pretains to the gear cluster and shift forks being compatible with the Z31 case (specifically the rear case). I have both a 87 Z31 71C and a 91 240SX 71C torn down in my garage. The front half is compatible and it could be assembled using the S13 back half, as I have seen before. The rear housing on the Z31 is very slightly different… the seal and guard are different, as are a couple other small things, but nothing major stands to at me. The main shift linkage appears to be the same length. The way I see it, I could spend hours measuring everything to compare or I could just ask here to see if someone else already did the work for me.
So the question is this:
Can I simply swap the 91 240SX gear cluster, shift forks and linkages directly into the Z31 case without issue?
Also:
Has anybody documented the subtle differences in all/some of the Nissan 71C manual transmissions?
Thanks! -
Re: 71C internals - are Z31 and 240SX CASE compatible
Some of the C-series truck transmissions were documented on the mini trucker sites showing compatibility with the 240sx transmissions. Although the same bolt pattern as the 240sx the trucks have a different bellhousing and a shorter tailshaft. Some had swapped the gear clusters into the truck transmissions from the 240s as well but this had all been documented a long time ago and many of those sites are down now. Its worth asking around on those sites though, some of the pics may have even made it over to NICO."Its the s12's sexy over weight step daughter, the z31" -
Re: 71C internals - are Z31 and 240SX CASE compatible
I have swapped 240sx 71c internals into a z31 71c case a few years ago. It works.Bolt on, fast, z31. You can only pick two.
Old weaksauce numbers: 391hp/433tq
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Re: 71C internals - are Z31 and 240SX CASE compatible
Outstanding, Thanks!Matt89 wrote: I have swapped 240sx 71c internals into a z31 71c case a few years ago. It works. -
Re: 71C internals - are Z31 and 240SX CASE compatible
I can remember reading a thread about the s13/14 71c differences. Based off of the year of the car it came out of, the later the year the larger the gear faces. z31 is the smallest faced gears and 98 s14 71c has the largest. I was just looking for power capability and interchangeability with the rb20det/rb25de 71c trans'.
Shiro Special # 981 Being assembled in my spare time Chromoly acquired!
Originally posted by BoostedMamma -
Re: 71C internals - are Z31 and 240SX CASE compatible
when you say you swapped, did you have to pick and choose with much measuring and checking a lot of clearances and whatnot- or did you just eyeball and swap?Matt89 wrote: I have swapped 240sx 71c internals into a z31 71c case a few years ago. It works.
I think the main question is how much of it can be used. -
Re: 71C internals - are Z31 and 240SX CASE compatible
s13 gearbox has a wider second gear cluster. This means the gears are different, output shaft is different, and i guess the counter cluster? it has been many years.
if you swap it all as one from one case to the other it will all swap fine. You can even mix and match as long as you have teh second gear components all matched up.
z31 trans - second gear gives first (yeah those teeth come right off, once one goes, they all go)
240sx trans - output shaft sheers first.
Either way, I'm hell on gear boxes. -
Re: 71C internals - are Z31 and 240SX CASE compatible
Been a while man! Good to see you on here.Tempestas wrote: s13 gearbox has a wider second gear cluster. This means the gears are different, output shaft is different, and i guess the counter cluster? it has been many years.
if you swap it all as one from one case to the other it will all swap fine. You can even mix and match as long as you have teh second gear components all matched up.
z31 trans - second gear gives first (yeah those teeth come right off, once one goes, they all go)
240sx trans - output shaft sheers first.
Either way, I'm hell on gear boxes.
I put it together last night… easy. I just swapped the entire S13 cluster into the Z31's 71c housing. It shifts fine on the bench. Now I just have to find some time to put it in and hope it will last at least until I can afford to put a 30A in there. The biggest factor is if I can refrain from flat-footing and banging gears the way I do with the 30A in my 84.
The input and output shafts looked identical… so I wonder if there is a material difference??? I think I would rather have second gear take a hike than the output shaft… -
Re: 71C internals - are Z31 and 240SX CASE compatible
the only difference is the step or land for second gear is wider to accommodate.
Not really a big difference, i was just half joking, however i did destroy the z31 via de-toothing second gear and noticed s13 was wider, and i'm pretty sure it was the s13 one i sheered the output shaft on. Nice clean break. -
Re: 71C internals - are Z31 and 240SX CASE compatible
Gotcha… Kind of a small sample… so I can still assume they are essentially the same overall.Tempestas wrote: the only difference is the step or land for second gear is wider to accommodate.
Not really a big difference, i was just half joking, however i did destroy the z31 via de-toothing second gear and noticed s13 was wider, and i'm pretty sure it was the s13 one i sheered the output shaft on. Nice clean break.
Interesting you took out the 2nd gear and not the counter gear. I took the teeth off the counter shaft input gear on a 30A a couple years back. It's about 50-60% wider than the 71C… -
Re: 71C internals - are Z31 and 240SX CASE compatible
[quote]Careless wrote:Everything. I did not disassemble the gear set. Just swapped the cases.Originally posted by Matt89Bolt on, fast, z31. You can only pick two.
Old weaksauce numbers: 391hp/433tq
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Re: 71C internals - are Z31 and 240SX CASE compatible
[quote]Matt89 wrote:Just for reference purposes: Same here, and it works fine.Originally posted by Careless -
Re: 71C internals - are Z31 and 240SX CASE compatible
I have used a 240 (usdm) gearbox and currently using a SR (jdm) gearbox.....honestly I can't tell any difference in acceleration or MPG…but they work just fine :-D
note: when I swapped gearboxes, I just removed the front cover plate and snap rings and shims, removed the outer case bolts and used a thin (but strong) chisel and seperated the gearbox from the bellhousing. Everything else bolts right up.sigpic
NWN Moderator
FertilePower on XboxLive -
Re: 71C internals - are Z31 and 240SX CASE compatible
Can this be stickied?Hmmm, Whats next?
Full Size Bronco, smashing shit.
84ZXT -
Re: 71C internals - are Z31 and 240SX CASE compatible
Fo sho!shromy wrote: Can this be stickied?
also edited title and first post to reflect the basic conclusion.
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