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

Re: Gearbox Question 1939 / 1940
 

Yes

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.

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.

Re: Gearbox Question 1939 / 1940
 

Sent you a PM Phil

Re: Gearbox Question 1939 / 1940
 

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

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?

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.