6-Speed NB2 Transmission Shifter Problem
#1
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I know that the 6-speed shifters in the NB transmissions are not known to be the most precise shifting transmissions in the world out of the box, but after installing mine on my NA I noticed a larger than normal amount of shifter slop/play. I summed this up to the typical crappy 6-speed shifter characteristics initially and thought nothing of it.
Over the last couple weeks however it has gotten significantly worse, so much so that I can no longer get it into reverse at all. There's about an inch and a half of side-to-side play in neutral and virtually every other gear in which the shifter is doing absolutely nothing. I took apart the shifter assembly completely yesterday and checked the screw that holds the shifter socket to the shift fork because I've read that that can come loose and cause this problem, however it was all tight, and you can see the shaft move along with the shifter:
https://photos.app.goo.gl/Ecyo4F5SNyhHyvRC3
Any ideas on what the problem could be? Easy fix worth doing myself/having repaired, or should I just get a new one? Transmission works perfectly otherwise.
Thanks!
Over the last couple weeks however it has gotten significantly worse, so much so that I can no longer get it into reverse at all. There's about an inch and a half of side-to-side play in neutral and virtually every other gear in which the shifter is doing absolutely nothing. I took apart the shifter assembly completely yesterday and checked the screw that holds the shifter socket to the shift fork because I've read that that can come loose and cause this problem, however it was all tight, and you can see the shaft move along with the shifter:
https://photos.app.goo.gl/Ecyo4F5SNyhHyvRC3
Any ideas on what the problem could be? Easy fix worth doing myself/having repaired, or should I just get a new one? Transmission works perfectly otherwise.
Thanks!
#3
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I have a brand new bushing in there, that was my first thought as well but it seems to be something further inside as the play is present even without the shifter in at all as I showed in the video.
That side to side movement I show at the beginning of the video is all free play, no forks or rods are being moved with that movement.
That side to side movement I show at the beginning of the video is all free play, no forks or rods are being moved with that movement.
#5
![Default](https://www.miataturbo.net/images/icons/icon1.gif)
Either the forks, or where the shift rod goes in and it is bent where it engages the forks. All of which require removal and disassembly of the transmission to diagnose. Now a days, 6 speeds aren't $1000 any more, and I can get em locally for $350-500 when mine let go (I've only killed one).
It has been years since I have had one apart, and it is fuzzy because of years of well... you know. Now with the influx of low priced 6 speeds, I haven't popped one open in a bit. The one I tore down had your symptoms and I expected to see issues with the 5-R shift fork but everything was in spec. I reassembled it using a RX-8 primary shaft and shift forks, retaining the NB secondary shaft and that is the trans currently in my car. I'll pick up a 6 speed every little bit as an extra, but end up selling it when I see an opportunity for a little profit.
Alternatively, there is a bushing that supports the control rod, that could be worn. It could also be an issue where the control rod engages the shift selector rod at the transmission. All of this would be evident if you were to remove the tail housing of the transmission. I highly doubt the 10 mil bolt that hooks the socket to the control shaft came undone.
You could theoretically drop the tail housing with the trans still in the car. I'm not sure if it is something I would do, however.
Edit: You could probably see that little bushing with the shift turret removed and the socket removed from the end of that control rod, the one you were trying to tighten up.
It has been years since I have had one apart, and it is fuzzy because of years of well... you know. Now with the influx of low priced 6 speeds, I haven't popped one open in a bit. The one I tore down had your symptoms and I expected to see issues with the 5-R shift fork but everything was in spec. I reassembled it using a RX-8 primary shaft and shift forks, retaining the NB secondary shaft and that is the trans currently in my car. I'll pick up a 6 speed every little bit as an extra, but end up selling it when I see an opportunity for a little profit.
Alternatively, there is a bushing that supports the control rod, that could be worn. It could also be an issue where the control rod engages the shift selector rod at the transmission. All of this would be evident if you were to remove the tail housing of the transmission. I highly doubt the 10 mil bolt that hooks the socket to the control shaft came undone.
You could theoretically drop the tail housing with the trans still in the car. I'm not sure if it is something I would do, however.
Edit: You could probably see that little bushing with the shift turret removed and the socket removed from the end of that control rod, the one you were trying to tighten up.