1939 gearbox question

[Henry Hopper]

I see that the '39 boxes are sought after by many as they are supposed to be better than the other years, due to extra strength, I think.

My question is, why just '39..... Did they revert to pre '39 design again in 1940.... Or is the '39 box the same and just carries the 39 name as a way of identity?

I can't see why they would build in improvements and then change it.

Just curious.

[woodypecker]

1940 is column shift

[Bassman/NZ]

39 did have advantages, but they changed to side shift, so 39 is the toploader with slightly better forks, double detent springs etc. However, a 37-38 box works just as well in my opinion, and doesn't have the price of a 39.

[Bruce Lancaster]

Also, not nearly all actual 1939's got the improved synchros...by about 1940 they were in full use, sideshift in cars and top shift in many pickups.
You could regard the hotrod need as being for a topshift trans with late type gears and syncros...which can be built in various ways using common sideshift parts correctly used in any topshift case back to '32.
You NEED Mac Van Pelt's book, a great summary of all you need to know.
While you wait for it, here is a smaller summary of what's out there, what you need, how to identify what is inside a transmission...which is frequently different from what is stock, as hotrodders have been swapping bits for decades:

http://www.jalopyjournal.com/forum/s...ices&showall=1

[Mart]

Bassman has said it, and that's as I understand it.

In 1940 Ford went to side shift. In 1939, (possibly in preparation for the side shift) they intro'd an improved design of synchro. (Not in all models, maybe Deluxe only). So in 1939 only, you had a top shift box with the better synchro (it is really a more superior design) and torque tube drive.

Pickups retained the top shift and improved synchro, but went open drive from 42, and used the 40 style clutch release in 40/41.

So, in days gone by, if you wanted a new box to replace the one you just blew up in your jalopy, you'd scour the yards looking for a 39 box, as it is the only year that had everything you wanted - top shift; better synchro; closed drive; lever type release.

Mart.

[Bruce Lancaster]

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The new parts actually carried 1938 Ford part numbers, and were first used in 1938 Zephyrs!

[Bassman/NZ]

And in typical Ford manner, some double detent tops still had the narrow forks and presumably the 38 synchros.

[Henry Hopper]

I never knew that column shift became standard, I thought it was an option.....you live and learn.It all makes sense now.Ive only ever been interested in pre 40 Fords and know next to nothing on the modern post 40 stuff.lol.

Thanks for enlightening me guys.

[flat-v8]

I have been kinda worried about my transmission, it does seem to shift ok, not great, feels fragile so I shift it very slow & easy, and it will sometimes get stuck, but has never slipped out of gear. It was rusty inside when I opened it up, the 600W molasses crap that was in there, was very nasty and stunk like hell! I drained it out and cleaned inside with degreaser rags, then refilled with 140 weight. I do wish I knew exactly what year and type it is??? Years & years ago, swap meet guy said it was a 1939, but I have never really tried to down shift, I go to netural then stop!

[Bruce Lancaster]

Flat, read through the link I posted. You date the case via the serial on it, then check out the innards to see what's what in case things have been swapped.
Look at your lid and see if it's the big or small screw type, 68 or 81 mark.
I think I am seeing a stock '36-8-'39 small synchro case and gears there. Getting rid of the 600 should make it happier!

[jerry grayson]

Originally Posted by Henry Hopper

I see that the '39 boxes are sought after by many as they are supposed to be better than the other years, due to extra strength, I think.

My question is, why just '39..... Did they revert to pre '39 design again in 1940.... Or is the '39 box the same and just carries the 39 name as a way of identity?

I can't see why they would build in improvements and then change it.

Just curious.

Late 39 and all 39 mercury had the improved syncro and shifted better. Not especially stronger, just shifted better.

[Bruce Lancaster]

On the strength, the actual gear teeth are the same from '36 on. Only the nubbins and ring surface changed.

[Fe26]

Nubbins? Now there's a word you don't hear everyday...

[Bruce Lancaster]

Technical jargon.

[ford38v8]

Originally Posted by Fe26

Nubbins? Now there's a word you don't hear everyday...

Oh... Really? Tell that to my wife please!

[Terry,OH]

flat-V8: Your transmission seems to have the better syncro and gears (first/ reverse slider on a helix shaft). With all the rust inside you may want to consider disassembly and cleaning and rust removal. New oil is not going to remove rust, nor stop the rust from doing further damage, to the input and output main bearings as well as the input shaft and cluster shaft bearings. There should be no reason why you should not try to downshift from 3 to 2nd at this point.

[flat-v8]

Originally Posted by Terry,OH

flat-V8: Your transmission seems to have the better syncro and gears (first/ reverse slider on a helix shaft). With all the rust inside you may want to consider disassembly and cleaning and rust removal. New oil is not going to remove rust, nor stop the rust from doing further damage, to the input and output main bearings as well as the input shaft and cluster shaft bearings. There should be no reason why you should not try to downshift from 3 to 2nd at this point.

Thanks Terry! Yes I should open it up, clean it up, & refill, but I do not want to pull the transmission at this point, maybe later when I'm retard!

[Talkwrench]

I love nubbins'

[Talkwrench]

When your RETARD??? mmm well transmissions can be hard but ...Be kinder to yourself

[Shadetree]

Originally Posted by Mart

Bassman has said it, and that's as I understand it.

In 1940 Ford went to side shift. In 1939, (possibly in preparation for the side shift) they intro'd an improved design of synchro. (Not in all models, maybe Deluxe only). So in 1939 only, you had a top shift box with the better synchro (it is really a more superior design) and torque tube drive.

Pickups retained the top shift and improved synchro, but went open drive from 42, and used the 40 style clutch release in 40/41.

So, in days gone by, if you wanted a new box to replace the one you just blew up in your jalopy, you'd scour the yards looking for a 39 box, as it is the only year that had everything you wanted - top shift; better synchro; closed drive; lever type release.

Mart.

Mart,
I have what I believe to be a 1941 floor shift pickup transmission. Other than the clutch set up it seems to be interchangeable. It also has the double detent springs. I was hoping to use it as a back up for my `35 Cabriolet. Will it work?

Thanks,
Bud Reynolds

[Mart]

Originally Posted by Shadetree

Mart,
I have what I believe to be a 1941 floor shift pickup transmission. Other than the clutch set up it seems to be interchangeable. It also has the double detent springs. I was hoping to use it as a back up for my `35 Cabriolet. Will it work?

Thanks,
Bud Reynolds

I think so.

Probably worth having a peek inside, do a tooth count etc. Like Bruce says, you never know whom may have got their hands dirty inside there in the past.

Mart.

[Terry,OH]

Shadetree: The transmission case and internals will fit the 35 without problems. Have to change the clutch release lever on the side of the transmission to the 35 lever, and use the 35 rear bearing retainer (motor mount). The 35 transmission cover (floor pan) will have to be modified slightly to accept the later transmission top, which has to be used due to the 3" shift fork, the shifter has to be changed to the 36 or later because the rod going into the top of the transmission for 35 is different and will not work with the double detent top.

[RPM]

Other than the shifter handle, isn't the 40 and 41 half ton 3 speed truck trans the same as a 39 passenger car? At least insofar as ratios and interchangebility?

[37 Coupe]

The green parts book shows the #78 prefix transmission case,which was first used on the 1937 Ford-1939 Ford passenger cars as used on the 40-42 pickup and I think up to 1947,for the three speed.

[Shadetree]

Thanks guys. I may never need it but good to have with all my other plunder. I took the top off when I first bought it and it looks great. To me it isn't worth the effort to change the original transmission out just to get a synchronized second gear and to keep it in second going down hill...

[Bruce Lancaster]

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Shade tree, I think you can derust the cogs where they are with little trouble using EvapoRust...I've used it on all sorts of things including complicated assemblies and as advertised, it does not attack anything but rust. Clean the oil off of gears with blasts of spray brake cleaner, which can drip on out the bottom. Fill the thing up with Evaporust, the gallon you need would be about $20, rotate things as needed, give it a few hours. When you drain it out the ER will likely be contaminated by oil from bearings and stuff, but it'll be worth the cost over taking the car apart. Any residue can be flushed out with hot water, fill the thing back up with your gear oil and rotate all to oil the bearings and gears before re-rusting happens. This stuff is excellent and truly harmless.
Run car around the block, drain out some of the oil to clear out whatever remaining water based stuff leaches out of cluster and bearings.