39 gearbox problem with 2nd gear

[pooch]

I am new to this 39 gearbox .

It all looks OK, but when second is selected, the fork does not push the ring far enough backwards to engage second.

Nothing seems bent and the forks are moving all the way and clicking into the idents .

When carefully lifting top off, the selector ring is about 1/4 inch shy of being right back and one syncro ring is showing .

It seems almost as if second gear is 1/4 inch too far back. because the top plate and stick and forks look fine.

What should I look for ?

[alchemy]

Who put the transmission together, and what parts did he use? Was it working correctly previously?

[pooch]

Dunno, I only just bought it , no history .

[bobH]

Who, and what parts = right questions. Sounds a little like 'early' shifter (fork & top), and 'late' syncro.
Someone will likely ask for more info, like evidence of modified 2-3 fork?, description of syncro, perhaps picts. Just my opinion

[DD931]

What's the part number cast into the tower?

[xix32]

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Does the syncro drum with the slot for the 2nd/3rd shift fork look like this one?
and does the shift fork have a "91-A " part number on it ?

[V12Bill]

Is the synchronizer body installed backward? See picture above.

[rotorwrench]

I believe the late type fork is now being reproduced . I've seen several that folks tried to widen with a file but it still doesn't correctly position the synchroniser.

[JonC]

It is being produced for about $250, ouch I just bought one.

[GEOFFNZ]

Is the lock ring in place that holds second gear in position. Cheers

[glennsanders]

I had one that did that ,the trushed washer was broken. Like he said

[pooch]

Thanks for all the replies and PM/s, a ground out early fork now seems very plausible.

Is it possible to modify this early fork to work with the extra throw needed ?

Does the actual box innards look OK and is 39 or later ?

Cast number under shift top is 40 7222

Here are the pics.





BTW, this motor/box is going in my next project, a 28 model A hiboy roadster.

I have a dizzy Q, new topic.

[pinstriper40]

I've got a shift tower with a '39 91A fork if you need one. PM me. The tower is junk, but the fork is the correct 91A fork that you need and you can install it on the shift rails in your tower.
Joel

[pooch]

Thanks for offer Joel.

Is the correct fork designed a bit further back is all ?

Does this push into 3rd correctly if mated with the early tower ?

[pooch]

Got some more pics.....

The fork throw is just one inch ( 2 7/8ths in 2nd and 1 7/8ths in 3rd ) measured from front of top plate.

The throw from 2nd and 3rd fully in is 1 1/4 inches.

If only the fork is changed, I will still be missing 1/4 inch ?

Bear with me, the last flattie I had was a '39 but that was in '68, and I never went inside the gearbox back then.

[bobH]

Pooch posted tower # 40-xxxx... Ain't no way. That's a 33-34 p/n. It's the 'short-shifter', meaning the distance from the top shift ball (pivot), to the small bottom ball is short. He needs the later tower, with the longer 'shift'. Ideally, I'd like the 39-style, with the improved detents, but he can also make it work with pre-39 tower that has the 'long' shift lever. I think approx 36 to 39 standard (someone will probably correct/refine this).
Of course, the correct, 39-style fork is needed.
Having said this, I would add that someone who doesn't know, put this together. I would double check everything. Probably can take apart and check, about as fast as I'm able to type and post.
Just curiosity, what CASE casting number did they use?
JMO

[rotorwrench]

There were at least three designs of shift top for the V8 type cars in the 30s. The early type has a rearward angle to the shift top tower. The second design has a vertical shift top tower but is only a single detent type. These were all used with the early style synchro. The third type is a vertical tower with two or double detents. Either of the two vertical tower types will work OK with the 91A shift fork but the double detent is the better of the two later types.

Your box does have the later type synchro but I can't tell what top or forks you have. The 91A fork has a similar throw to the older ones but the throw is repositioned to work with the later 3-inch synchro in a different location.

Mac VanPelts transmission book has the answers to any question a guy would ever have about these old transmissions. Several parts sources carry them now.

[Mac VP]

Wrong tower. Wrong forks. That would never shift correctly even if you changed out the 2nd/high fork to the 91A-7230 fork. You'll need a 36-39 tower with its correct low/rev fork AND the 91A fork in it. This type tower needs the 36-39 shift lever to operate properly.

Your high gear synchro ring looks worn in the pic....can't tell on the second gear ring.

Get the right parts and put it together correctly and you won't regret the time or cost spent to do so.

[d.j. moordigian]

My 3" fork doesn't look like that...
I believe it has a wrong fork (2 3/4"), that was modified too 3"...