Model A to Model B Transmission Swap 2023 Project

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Happy New Year!

I purchased an early Model B gearbox a while back at a good price, (3 years ago!! but never took things any further but now back on the radar) not in the best condition but appears to be serviceable. The other parts I’ve been gathering with the help of John Cochran. (need any Model A bits, he’s your man)

There are a fair number of parts needed to complete the conversion, but I think it’s worthwhile as its a synchronised transmission. The later unit is supposed to be a better option but we’ll work with what we have and it’s a good project to take into 2023.

As you can see some of the parts need some work. There are a number of differences between the Model A and Model B set up. Major items are the clutch housing, flywheel, relocation of the pedals and wishbones just to mention a few.

Made a start on the shift tower which had some rust and debris that has fallen into the gearbox, this however should be easy to remove. The unit was filled will gear oil when I originally purchased it to keep things lubricated during storage. As you can see even with a cursory initial clean up on the shift tower, things look a lot better.

During the clean up I came across the part number which is cast into the casing, stating 40-7222, which was a little confusing as this is the earlier transmission.

A quick check over at the excellent VanPelt site quickly solved the mystery

The 40-7222 shifter housing (known as the “slanted” tower) pictured below was used from 1933 through 1935 models. The B-7222 housing (1932 only) looked the same but had two mounting bosses on the right hand side for the parking brake handle mount. Both early housings incorporated the B-7235 shift lever guide plate (see picture at bottom of this page). The guide plate was discontinued after 1934 production. The early housings used the B-7230 and B-7231 forks through 1933 and perhaps part of 1934 production. The slanted towers used the smaller 7230/7231 shifter forks, but also used the smaller shifter levers. Although it will bolt on to any 1932-52 toploader gearbox case, it can NOT be used with the 1939 and later gear sets with the late style synchronizers. This housing is the single detent type, using the same detent spring and plungers as the 68-7222 housing.

Work continues!

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