Who rebuilds ford flathead transmissions

[John Koontz]

Hi anyone know of a reliable rebuilder for a 1940 ford flathead side shift transmission? I rebuilt it myself but it keeps getting stuck in 2nd gear? If you know of anyone or you have theory why it keeps getting stuck. (The side shifter seems to be ok. if I take the side shifter off I can slip it out of second with my fingers) Thanks for the help.

[Angledrive]

Mac Vanpelt, Vanpelt Sales

[Tim Ayers]

John:

Let's think about this. If you are able to manually shift the trans with the cover off and your fingers, I would have to believe the issue is either with the fork and arms or the linkage rods from the steering column.

I don't deal with side shift transmissions, but I would make sure and double check that all of the linkage is adjusted correctly.

It's possible that the linkage is too loose and allowing the synchro to slide too far in it's engagement and the blockers are getting to the point of almost coming out. This would lock it up for sure.

Before you pull the trans out of the car, I would really look at all linkage points first.

[51504bat]

Since you're in orange County you might want to check with CW Moss to see if they can recommend someone regarding your issues. since they're right in your backyard. Or just a short ride up the 57 is The Old Ford Store in San Dimas. They might be able to recommend someone as well.

[Kube]

I believe Tim has offered you sound advice.
My guess is also a linkage issue. Either the bushings (both ends perhaps) are worn and / or the levers are not adjusted correctly.

[Seth Swoboda]

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Can you shift the gears with the cover on using just the levers on the side?

I recently rebuilt a '39 transmission. I put it in the car and it popped out of 2nd. I removed the transmission. Took it apart and put it back together again. Carefully checking all my clearances. It still popped out of second. Now this was not the first transmission I have rebuilt. I knew my work inside was all correct. The one thing I had not checked was the shift fork. Although the double detent top was rebuilt too, I had not noticed that the shift fork was slightly bent. In fact, it was barely visible to the eye. I put a different shift tower and forks on it and it worked perfectly. The bent fork would not allow scecond gear to be pushed back far enough to engage fully. That was the first time I've had that issue. That cost me 8 hours of extra work.

[jayvee34]

I recall the same problem in my 40 Ford sedan. I replaced the worn bushings in the
shifting rods. Problem solved.

[rotorwrench]

Popping out of 2nd gear is one of the most common problems with these old gearboxes. It usually pops out during thrust load changes, ie the transfer from throttle on to throttle off. The thrust load reverses and if there is either too much play in the countershaft or the 2nd gear bushing then it can pop right out no matter how well the detent in the shift housing works.

[PeteVS]

Were all the side shift transmissions equipped with the later synchros? I put my top shifter together with later synchros but the earlier 2nd gear fork. (The previous owner of the fork must have ground it out to fit over the sleeve but the fork was 1/4" shy of engaging 2nd.)

[raybee]

Must use the 91A fork to work properly.

[Tim Ayers]

Originally Posted by rotorwrench

Popping out of 2nd gear is on of the most common problems with these old gearboxes. It usually pops out during thrust load changes, ie the transfer from throttle on to throttle off. The thrust load reverses and if there is either too much play in the countershaft or the 2nd gear bushing then it can pop right out no matter how well the detent in the shift housing works.

The OP's trans isn't popping out of 2nd, it is locking up in 2nd. This is sometimes causes when the synchro is allowed to be thrown too far forward or aft.

[Tim Ayers]

Originally Posted by PeteVS

Were all the side shift transmissions equipped with the later synchros? I put my top shifter together with later synchros but the earlier 2nd gear fork. (The previous owner of the fork must have ground it out to fit over the sleeve but the fork was 1/4" shy of engaging 2nd.)

Yes. They all had the improved synchro.

[1942deluxe]

Charlie NY rebuilt mine on the 42 Ford. Little bit of whine in first but stays in 2nd gear going down steep hills. My 48 is fine on reasonably level ground but pops out of second on a steep hill when it feels like it.

[Tim Ayers]

Originally Posted by 1942deluxe

Charlie NY rebuilt mine on the 42 Ford. Little bit of whine in first but stays in 2nd gear going down steep hills. My 48 is fine on reasonably level ground but pops out of second on a steep hill when it feels like it.

Unfortunately, the only proper fix for the popping out of 2nd issue is a rebuild.

[Terry,OH]

The adjustment of the shift linkage sounds like a good first step.

[1942deluxe]

Tim, I agree. Talked to Mac when that started and that was his answer also. I put new shifter bushings in and it didn't change anything. The oil pan is sketchy (JB weld on it) and I have a NOS one to replace it. When I do that sounds like a good time for a transmission rebuild while things are apart. When I got the car we were living in the coal region of PA which is nothing but mountains and it happened much more often.

[Seth Swoboda]

Originally Posted by PeteVS

Were all the side shift transmissions equipped with the later synchros? I put my top shifter together with later synchros but the earlier 2nd gear fork. (The previous owner of the fork must have ground it out to fit over the sleeve but the fork was 1/4" shy of engaging 2nd.)

The '39 style synchronizer used a 3 inch shift fork. The earlier shift forks were 2 7/8 in, I believe. Yes, you could grind the smaller shift fork to fit. The correct thing to do is get the 3 in shift fork.

[uncle buck]

possibly Dennis Lacey in Covina?

[Tim Ayers]

Originally Posted by Seth Swoboda

The '39 style synchronizer used a 3 inch shift fork. The earlier shift forks were 2 7/8 in, I believe. Yes, you could grind the smaller shift fork to fit. The correct thing to do is get the 3 in shift fork.

Correct. I've seen a few of those early forked tops where folks grind them to fit the later, improved synchro. Doesn't work as PeteVS found out. Different angle and length.

[Kube]

Originally Posted by Seth Swoboda

The '39 style synchronizer used a 3 inch shift fork. The earlier shift forks were 2 7/8 in, I believe. Yes, you could grind the smaller shift fork to fit. The correct thing to do is get the 3 in shift fork.

I'm fairly certain the offset is different so grinding the earlier fork IS NOT a viable alternative.