Hello, all I have another question that I would like your collective wisdom to ponder. First, let me say, I know I’m being a lazy ass trying to get away with this, but I still would like to hear what the board has to say. I recently got stuck in second gear in my AV8. I just got done swapping in the flathead, and 39 trans. I drove it around the neighborhood a few times, and felt that the transmission (or something in the drivetrain) was making more noise than I was used to, but chalked it up to the vagaries of hot rods. I’m still not sure if it had anything to do with it getting stuck. I managed to get home, and park in my tiny garage with the help of my neighbor. I popped the top of the trans, and discovered one of the metal blockers in the synchro hub had managed to wedge itself up on the synchro ring causing the issue. Somewhat common from what I’ve read. I removed the tab (it almost fell out), and now the synchro slides freely between second, and third. Now, my question: Can I drive around on the other two blockers? I just finished the damn thing, and was telling my wife the other day that I’m glad I wouldn’t have to do any of that again (should have knocked on wood). I know the right, and proper thing to do would be to pull the trans, but I shudder thinking about undoing all my work in my tiny, 90F garage. Please give me your opinions, anecdotes, tales from the past, anything!
You can most likely drive if you shift either very slowly or "double clutch" it like the old, non synched transmissions. But it's quite likely the other two will eventually pop up also. There are variations in location of groove in the synchronizer outer sleeve that require that the top have matching fork positions. I ran into this situation back in the early '60s.
I think I’ll drive it, and report what happens. Perhaps we can all learn from my (possible) mistake. What do those blocker do anyway?
So, there is a reason that metal tab came loose (?) If it is the type that is held in place by the ball detent and spring where did they go ? If that ball gets between 2 engaged gears while they are in motion bad things will happen.Was this a "rebuilt" transmission or just a used one that someone has gone thru? In any event,i would pull the trans and go through it again. Just my 2 cents.Bob
Even one little detent ball stuck between the cluster and the input gear could cause a very expensive kablammo. Think about trying to push the cluster away from the input when the only thing holding them together is your cast iron case.
It’s the metal tab held in by the long wire springs. It looks like one of the ends of the tab was bent so it didn’t hook into that metal wire spring properly. The gears were gone thru recently, but took it out of the side shift case to put it in my top load case. Was the tab like that when I put it together? I really can’t remember at that level of detail. I’m not Adrian Monk!
I could, but I really, really don’t want to pull the engine, take apart the trans, and put it all back together again so recently after I got it on the road. Months of work down the tube. I love tinkering, but driving the damn thing is the end game.
FIX IT now or you will soon be paying big bucks for a rebuild parts when the other blockers come loose and wedge between the gears.
The tabs help to position the sliding hub...Some here say wire springs, but did the 39 have balls and coil springs.? As other's have said, fix it now...
It’s the wire spring, and tab. The internals are out of a later side shift case. You guys are right. I need to do it the right way, and pull it all apart. My Dad always told me “the lazy man works twice as hard”. I’ll save myself more work in the future. At least it’s going to be in the 70’s the next few days. Thanks for the encouragement!
I thought good, and hard about it! There doesn’t seem to be enough room to slip that metal tab under the synchro sleeve, but on top of the wire spring that is supposed to hold it secure.
Sometimes it’s a good thing to get away from the problem for a few days or weeks. Then come back to it like this is your buddy’s car and you want to help him make it right. The problem actually changes into a project…..something you look forward to. FWIW you definitely need to pull the transmission and tear it down. Put a new set of blocker inserts and springs in there and be sure to stagger the ends of the two wire springs so that they don’t end on the same insert.
OK l, after reading all posts again and learning that the innards came from a side shift box placed into a '39 case with a '39 shifter top. If this is so you have the exact same problem I had about 60 years ago! The late synchro sleeve likely has a synchro sleeve with the groove for the fork offset to the rear of the sleeve OD. The '39 shifter sleeve had the groove centrally located and the fork in the shifter located for that groove location. This caused the sleeve to be pushed too far off center, allowing the blocker plates to pop up and escape from beneath the sleeve. If this is the case, you will need a shifter top, or at least the proper forks, to match the groove location, most likely from a post'48 pickup trans.
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