A question came up on FB around the late S30/Early S130 5-speed transmissions.  The OP asked if there is supposed to be a return spring on the 1-2 gate as well as on the 5-R gate.  He stated that his only has a detent spring on the right side, but not the left side.  My transmission does the same thing, but I swear it is supposed to have the detent on both sides returning the shifter to the 3-4 gate, with a heavier spring on the right and a light spring on the left.  There seems to be conflicting info if there is supposed to be a detent spring on the left side.

If there is supposed to be a detent spring on the left, is it repairable without a complete teardown?  I assume not.

Observations and comment.  The Facebook link would probably help or the text copied and pasted for us non-Facebook people (there are a few left).  And, you went 1-2, 5-R, right-left, 3-4, right-left.  Hard to follow, besides use of the word "gate".  Not sure Nissan's system would be considered as having gates.  Also, without the Facebook post "same thing" is undefined.  Not clear what the problem is that's being discussed.

Are the springs not shown in the FSM control drawings?

Only posting because tranmsission stuff is interesting, and I like to practice my reading and comprehension.  I could be off.

Sorry Zed.  I purposely didn't link FB for that reason.  I will cut and paste the discussion without the posters' names. It sounds like there is no spring on the left side after a few new responses.

Here is the OP's question...

"Should my shift lever spring back to center from both the right and left? Currently it only springs back to center from the right.

This is a 5 speed from a 280ZX.

Thanks."

 

And here are a few of the responses...

"The people who say it should spring back from both sides are wrong. (Unless you have a turbo with a T56 or the KA24 5 speed upgrade).

The only spring on the 5 speed is from the reverse/5 gear position. The other side falls back towards center sometimes, but that’s just the linkages and forks putting pressure on the shifter."

 

"When I rebuilt my 5 speed I was sure that it was broken because you could feel the spring only on one side. Tearing into it I was suprised to find it was supposed to be that way. After doing some learning realized it was all the Datsun 4/5 speeds. But the way the forks and stuff are weighted it does naturally rest in the middle so it can seem like a return spring in there. Part of the reason I'm upgrading to the FS5W71C is they added the dual return over the 71B models. That and it being way more robust!"

 

I thought my old 4 and 5 speed transmissions had centering springs on both sides, but I could easily be wrong.  My current trans only returns on the right side.

Seems like there's only one spring but it does both left and right.  Doesn't it?  It sits on a flat (maybe a groove) on the "striking guide", and rotation of the guide takes it off of the center of the flat.  The spring pushes on both sides though to bring it back to center.

If I'm readng the drawing right.  9, 10 and 11.

p.s. it probably only has real effect when the guide is near center, with the plunger falling in to the stable position.  The whole Facebook conversation might be revolving aronud a misunderstanding of how it works and what is possible.

Edited November 7, 2024Nov 7 by Zed Head
guide

I can't tell from the FSM if the spring would act on both sides or not.

 

Can somebody tell me if their Z does or does feel like there is a detent spring on the left?  I used to have five 4-speed transmissions sitting in my garage before I moved across the country, but I gave them all away.  I don't have anything else to compare it to now.

My 77 5-speed shifter does rest in center 3-4 position if you aren't pushing it to one side or the other. There is something pushing it away from 1-2.

The spring pushing away from 5-R is much stronger than the force pushing away from 1-2. Might just be the rubber boots and linkage stuff, but there is something.

My '71 4 speed parks between 3 & 4 and like CO says, the push from R is much stronger, definitely a spring. It like "just glides" to there from between 1 & 2 with not really a discernable spring type push to the right.

That is about what I remember.  Mine has nothing on the left.  When I do a 2-3 shift, I have to aim the shifter to the right.  In the past, I always remember the shifter gliding from the 1-2 gate into the 3-4 gate.

13 hours ago, Jeff G 78 said:

He stated that his only has a detent spring on the right side, but not the left side.

This is one of the confusing things in the first post.  Is the guy actually seeing a spring or is he feeling a return-force and assuming a spring?

I wonder if the return spring plunger #11, and/or the groove/flat, suffer wear over the years.  Seems like they would be under high pressure, with a small contact area and high leverage.  I'll bet that's a strong spring.

New rabbit hole!!!

Just for grins. I'm pretty sure that my old stick cars - 2 Maxima's, Stanza, Jeep Loredo, 1st 240Z, Chevy Vega all parked between 3 & 4.

Poop and laughter.  I went to my old standby, the carparts.com site and searched around for the part numbers to see if I could find some images.  Found some on an Arabic langauge site.  It's odd, the numbers match but the label says "plunger reverse" not plunger return.  Anyway, something to look at.

p.s. I browsed around some rebuild videos and it's funny how nobody really pays any attention to the parts in the tail shaft case.  

https://www.carpartsmanual.com/datsun/Z-1969-1978/power-train/transmission-control/5-speed

https://haraj.com.sa/1117916900/قطع_قير_دتسن_80_85/

Based on that info, I'd say there is only a detent spring on the reverse side, but???  Thanks for taking the time to research it.

Paid attention while driving my 77 yesterday. I think it's just the rubber boots that pushes my shifter away from 1-2. I don't think there are any intentional springs on that side.