The Ford Barn

phil pavicich · 10-26-2019, 06:49 AM

Hi Guys , my question is will the internals of a 1940 ford 3 sp gearbox (side shift) fit into a 1939 ford toploader gearbox , i have a good 40 model box and am trying to find out if i can fit the internals into a 39 box with top shift , i have a 39 box with no internals
thanks in advance Phil
Perth Australia

Angledrive · 10-26-2019, 06:51 AM

Yes

Juergen · 10-26-2019, 07:07 AM

But for your "39" shift top to work it should have the big fork with the 81A- part number embossed on it. Early 39s used the older fork.

JM 35 Sedan · 10-26-2019, 08:53 AM

The later gear sets from a side shift trans will definitely go into a '39 top load case, as well as the earlier top load cases. I just put the later 29 tooth cluster/15 tooth input gears into a 35 top load case, (along with having 3.54 ring & pinion in rear) and the quality of shifting is so much better than it was with the original 35 gears, like night vs. day, and this also seems to have eliminated the jumping out of 2nd gear. However, this could be mostly due to making sure all gears, spacers, etc., had nominal to minimum clearances.

I should also note that I did not use a 39 style shift tower, with the standard/original wide fork. A friend made a presission set of special forks, where all pieces required were tig welded together, that assembled directly into the stock 35 shift tower that slants back towards the rear of the car.

Talkwrench · 10-27-2019, 08:31 PM

Sent you a PM Phil

ford38v8 · 10-27-2019, 11:55 PM

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Quote:

Originally Posted by Juergen

But for your "39" shift top to work it should have the big fork with the 81A- part number embossed on it. Early 39s used the older fork.

I'm sure you meant to say 91A, and no part number, just the large 91A cast into the bottom of the large fork.

frnkeore · 10-28-2019, 11:01 AM

I have a question.

The early fork is 2.81 wide and the 91A is 2.98 wide, both by Ford specs. Can the early fork be machined to the late width?

FritzJr · 10-28-2019, 01:36 PM

The difference in the forks is not only the width of the opening but also the offset. The early fork will not function properly, even if it is opened up to fit over the synchro.

10-26-2019, 06:49 AM	#1
phil pavicich Member Join Date: Aug 2010 Location: australia Posts: 58	Gearbox Question 1939 / 1940 Hi Guys , my question is will the internals of a 1940 ford 3 sp gearbox (side shift) fit into a 1939 ford toploader gearbox , i have a good 40 model box and am trying to find out if i can fit the internals into a 39 box with top shift , i have a 39 box with no internals thanks in advance Phil Perth Australia

10-26-2019, 06:51 AM	#2
Angledrive Senior Member Join Date: May 2010 Location: Lakeland Florida Posts: 302	Re: Gearbox Question 1939 / 1940 Yes

10-26-2019, 07:07 AM	#3
Juergen Senior Member Join Date: May 2010 Posts: 500	Re: Gearbox Question 1939 / 1940 But for your "39" shift top to work it should have the big fork with the 81A- part number embossed on it. Early 39s used the older fork.

10-26-2019, 08:53 AM	#4
JM 35 Sedan Senior Member Join Date: May 2010 Location: Near Rising Sun, Maryland Posts: 10,858	Re: Gearbox Question 1939 / 1940 The later gear sets from a side shift trans will definitely go into a '39 top load case, as well as the earlier top load cases. I just put the later 29 tooth cluster/15 tooth input gears into a 35 top load case, (along with having 3.54 ring & pinion in rear) and the quality of shifting is so much better than it was with the original 35 gears, like night vs. day, and this also seems to have eliminated the jumping out of 2nd gear. However, this could be mostly due to making sure all gears, spacers, etc., had nominal to minimum clearances. I should also note that I did not use a 39 style shift tower, with the standard/original wide fork. A friend made a presission set of special forks, where all pieces required were tig welded together, that assembled directly into the stock 35 shift tower that slants back towards the rear of the car. __________________ *John* *"Never give up on what you really want to do. The person with big dreams is more powerful than one with all the facts". Albert Einstein* Last edited by JM 35 Sedan; 10-28-2019 at 08:25 AM.

10-27-2019, 08:31 PM	#5
Talkwrench Senior Member Join Date: Aug 2012 Location: Perth, Western Australia Posts: 2,687	Re: Gearbox Question 1939 / 1940 Sent you a PM Phil __________________ *"Came too close to dying to stop living now!"*

10-28-2019, 11:01 AM	#7
frnkeore Senior Member Join Date: Jul 2019 Location: Southern Oregon Posts: 782	Re: Gearbox Question 1939 / 1940 I have a question. The early fork is 2.81 wide and the 91A is 2.98 wide, both by Ford specs. Can the early fork be machined to the late width? __________________ Frank '35 Ford Model 51 '48 Ford F3 '54 Ford Tudor Mainline

10-28-2019, 01:36 PM	#8
FritzJr Senior Member Join Date: May 2010 Location: Northern Neck, VA Posts: 131	Re: Gearbox Question 1939 / 1940 The difference in the forks is not only the width of the opening but also the offset. The early fork will not function properly, even if it is opened up to fit over the synchro.

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