7 replies to this topic

[Andy Mitchell]

Hi,

 

When I backed out of my spot for our first sprint race today, my trans locked in reverse and wouldn't come out. Much screwing around ensued (as it always does when a race car breaks), but nothing we tried fixed the problem. I think there is a trans swap in my very near future, but I thought I'd ask here first in case someone has a miracle fix. 

 

It's a NB transmission in an NA car, if that matters. Synchros are fine, no funny noises, shifted fine before this happened. 5th gear is never used at this track. Lever is locked in the reverse position, you can't simultaneously select any other gears, and messing with the detent through the neutral light hole wiggles the shifter too. Pry on the detent with a stubby screwdriver and the whole thing moves, but won't go far enough to actually 'click' back into neutral.

 

I opened up the turret, and you get the same thing there - the shift rod (which is sitting nicely in the reverse position) moves about 1/4" rearward when you pry on it but then just refuses to go further. There's a sort of springy resistance to it, if you get my drift. Nothing I can see inside the turret is obstructing it's motion.

 

I know there are some other detent springs on the side of the case I could pull out, but is it worth continuing messing with this? I'm thinking it may be time to move on to the post-mort em phase, but if someone knows for sure what's up I'd much appreciate any advice they may wish to offer.

[Johnny D]

I think I remember some place on a youtube video that it's caught on the reverse switch. Take it out and should become unstuck.

I'm sure there's video online about it.

J~

[Johnny D]

[Andy Mitchell]

Thanks, but I knew about the reverse switch thing. I screwed up in my original post and called it the 'neutral light hole', but it was in fact the reverse switch I took out to diddle with the innards through. But that wasn't the issue, you can move the shift rod a bit that way but not enough to actually get it out of gear. And when you move the shift rod with a screwdriver through the hole, the shifter itself waggles around, meaning (I think) that it's actually selected properly.

 

Something seems jammed inside the main case, but I can't imagine what. Could bent or worn out shift forks on the other clusters do this?  

[Bench Racer]

I understand you did the shift switch, BUT the lever would not travel far enough to get the "click" into neutral. 

 

Read on a site that this stuck in reverse does happen to the NB transmissions. One guy with a street car had a helper watching the shift lever for movement and the helper pushed the clutch in while futzing and after 7-8 futzes, helper viewed shift lever movement, tried shift lever and moved thru all the gears. 

 

For more info search 1999 Miata stuck in reverse.

[SaulSpeedwell]

Peened over 5-R slider (massively forced shift), or broken brass synchro chip rattling around on the 5th side ("normal" fatigue from moderate long-term abuse of racing), or broken synchro spring (normal fatigue or result of one really rushed shift) on the 5th side.  The damage could have been done 5 minutes or 5 hours ago, and the part(s) have just now contributed to the lockout.  Forcing it will only stress out other parts.    Good luck!

[Andy Mitchell]

Thank you very much, both of you.

 

Mr. Bench, if there was any way wishing and hoping (along with prodding, wiggling, tapping and banging) would have fixed it, we'd have hit on it yesterday. Had the whole day to try, lol.

 

Mr. Speedwell, what you say has the ring of truth. Time to swap transmissions and read the entrails later on.

[Bench Racer]

Andy, for me skip the Mr.