gear stick return to central pos

[duncan11]

Hi, without me pulling the car apart, was wondering if anyone can tell me what forces the gear stick to return to its central position.
Mine struggles to return to centre from 5th , but seems ok from 2nd. Is it a spring ? I have had the boot up and greased where I can see on the gear stick mechanism, but it still is dodgy 5th to centre. Thanks for any help

[Smallblock454]

There is a weight at the gear shift mechanism at the gearbox.

You can check the gear box shift mechanism, but this sounds more like an gearbox rebuilt.

What gearbox oil do you use?
Is there a difference between cold and warm gearbox.

Regards, Markus

[jakeru]

Yes, there is a spring in the transmission that returns the selector rod to center position. However, if the returning feature is not returning reliably, it could instead be something elsewhere in the linkage has too much friction. Generally speaking, to troubleshoot this I'd start with the external linkage (and you already mentioned lubricating the shift console in the passenger compartment, but did you also check that the cables were moving freely, and did you look at the bellcrank "contraption" back at the transmission, where it translates one cables motion to selector rod rotation? All those parts are external to the transmission.)

Edit: this thread has some pictures and info about the "contraption" (I'd recommend checking and lubricating yours if you haven't already - it does come into play when moving the knob left or right!):
http://986forum.com/forums/general-discussions/60643-excessive-shifter-play.html

After ruling out all the external sources, it's time to go internal, but this will probably get expensive and likely mean swapping or rebuilding the transmission. It's possible that some springs may be accessible under cover plates, although if something with the selector shaft and shift fork (inside the transmission) is worn out or bent, it would require transmission disassembly to completely diagnose it and repair. Best of luck!

[duncan11]

thanks for your comments. My 6 speed box has not got the 'Contraption' you mentioned, the cables just go onto an arm that moves forward or backwards. thanks Duncan

[Smallblock454]

Hello Duncan,

the weights on the shift mechanism are responsible to get the shift lever back to center and help to get gears in.

The springs jeakeru mentioned are springs that press detends in, so the gears don't pop out. Maybe there is something wrong with a detend or a spring for your 5th gear.

You can check the cables. But in general this wouldn't affect only one gear.

Regards, Markus

[jakeru]

Marcus - that's an interesting theory about the weights returning the shifter to center. I believe, however, that the function of those weights is to provide additional inertia when shifting gears, to help the synchros work. (It is remarkable how different the 6-speed linkage is from the 5-speed!)

OP - good to know which transmission you're dealing with. Found a related thread here: 986S 6 speed trans issue

Edit: also, on the 6-speed transmission, G86.20, I think the attached picture will shed some light on what's going onside inside the transmission just behind those two selector input shafts.

The spring below the cover marked "A", which I believe also would be part number 996 303 255 00, is what I believe in this transmission would cause the left-right motion at the gear shift knob to return back to center track (3rd-4th gear track). The good news is that the workshop manual does have a procedure for accessing this spring, without requiring transmission disassembly. The bad news is the same spring also causes return from the other tracks (R, 1-2, 5-6) to center (3-4), so I doubt there could be much guarantee that simply replacing this spring will solve your problem. Have you changed the transmission fluid recently?

[Smallblock454]

Hello jakeru,

the 6-speed has 2 selector input shafts. The "big" one and the "little" one (green arrows). Cables go to the black rounded parts with the inner silver part on the photo.

As you can see, the weights on the big one are pretty massive (red arrow on top one).

Both selectors work together simultaneously. The big one has 3 rests / positions, not 6. And the little one is part of the differential housing.

Inertia. Hm, i would say weight instead of inertia. Maybe a translation problem. Not shure if we mean the same thing.

Spring A: yes you're right when it comes to the gear stick. But i think the mechnism is different on the 6-speed. I couldn't find a picture that shows the 2nd hole as in the diagram.

And that won't solve the problem of duncan11, because that will affect all gears. That's why i mentioned the springs of the gear detents. But i think there must be another internal problem with a claw or something else.

But considering this post of duncan11: http://986forum.com/forums/general-discussions/62915-gear-change.html maybe i would start with a change of spring A.

Regards, Markus