Floor Shift versus Side Shift

[bookertee]

When Buick introduced the "column shift" to replace the "floor shift" type transmission on the series 40 did they introduce all new internals, that being gearing, shafting etc, or did they simply design a new case that introduced the shifter fork system differently to pretty much the same internal working parts?

[sean1997]

I think it depends on which part you are looking at, but I think a complete set of internals from one year should fit another year on the smaller 5-bolt top cover trans for '36-'55. For some years Oldsmobile and Pontiac parts also fit. I have some pages from an interchange manual that covers '36-'48 and the section on transmissions is about 12 pages I can fax it to you or send it in an email as a PDF file if you want it.

[bookertee]

Sean, I would greatly appreciate an email with the transmission interchange data. Please send to bookertee4661@yahoo.com Thanks!

[1939_Buick]

1939 was the first year of column shift

Its was a new case, but some parts were a carry over from 1938. Some parts are common up to about 1955 (and with Olds, Ponti, & LaSalle). Buick changed some of the gearbox parts most years, or at least they have different part numbers.

[Guest DaveCorbin]

Just to clarify a bit:

!938 was the last year that had a standard floor shift lever. For 1939, Buick moved the back and forth motion to a side mounted single lever.The side to side motion is handled by a push/pull cable that is on the end of the shaft outside the back and forth lever. Both the lever and the cable go to the bottom of the steering column.It's a one year only arrangement. In 1940, Buick went to a two lever system tha's more like what you would see for many years. Internals are somewhat common from 36-55, dependent on series, exact year, etc. As noted, some of the big series boxes had some commonality with Cadillac. A parts book is a REAL necessity here !!

Regards, Dve Corbin

[sean1997]

I emailed the file, hopefully you received it and it helps. Are you converting your side shift to a top shift? I'm thinking about doing that with a '57 6-bolt top cover trans using the case and shifters from a '38 and the '57 internals. It looks like it should work but the '57 tailshaft will require some minor modification and a hole drilled and tapped in the rear of the '38 main case to match the tailshaft.

Also, the interchange manual only lists interchanges for parts that are exactly the same, but some parts may interchange with minor modifications or may fit the transmission but not the application. For example, for the 6-bolt top cover case the '38 and '57 main drive gears are different, but the '57 will fit in the '38 case without any modification. Same with the cluster gear. You just have to mix and match to get what you want.

[bookertee]

Sean, What I'm trying to do is to come up with a Buick floor shifted transmission for a custom application, but I want to use parts which are not "unique" or horribly expensive, and are also reliable. I thought that if internals of the earlier floor shifted boxes were interchangeable with the later column shifted boxes that there would be a much wider pool of available parts to use for the build and possible future rebuild if necessary. So far, from the info you and others have sent, it looks encouraging. If anyone else has added info please keep it coming. Thanks Sean and thanks to all. (PS this custom application will retain the torque tube output)

[sean1997]

If you are putting it behind a 248/263 straight 8 you should be fine with the 5-bolt top cover trans, but if it is going behind a 320 straight 8 or a V8 you should probably use the much stronger 6-bolt top cover trans. Buick used the 6-bolt top cover trans from '36-'60 (toploader in '36-'38), Pontiac used it up through '57, Oldsmobile used it up through '63 (open drive tailshaft started in '57) and Cadillac/LaSalle used it at least for '39-'53. There is an article in the August 1956 issue of Hot Rod about converting the bigger 6-bolt top cover trans for use in a '55 Chevy. It is available in a book called "The Best of Hot Rod Magazine 1949-1959". The title of the article is "Big Gears for Any Engine" (starts on page 164 of the book). See this link:

http://books.google.com/books?id=UXOQ-vBSzpEC&dq=the+best+of+hot+rod+magazine+1949&printsec=frontcover&source=web&ots=A279vyspN5&sig=2e81kZ9_5KCiFHOZvP7Z2yx5w-E#PPP1,M1

While not quite the same as the 5-bolt top cover trans, I think most of it still would apply, of course you don't need the open drive tailshaft if it is going in a Buick.

Also, see this thread for some more info on 3-speed conversions:

http://www.v8buick.com/showthread.php?t=149783

I took some pictures of my project today. The green trans is a stock '57 Buick trans and the other one is a '38 Buick main case and shifter assembly with '57 gears and tailshaft. I still need to modify the tailshaft to fit, but it isn't that much work (widen 3 holes and drill and tap one hole in the rear of the main case). Also, I noticed one thing that will have to be modified on the bell housing. The shifter rails protrude out of the front of the main case when shifted into certain gears. On the side shift case these are lower in the case with matching holes in the bell housing. On the top shift case they are near the top so the bell housing will require two matching holes. There are also several holes that will need plugs put into them where the master cylinder attached and one unused hole in the rear of the main case.

[bookertee]

Sean, Wow, you are a wealth of knowledge on this subject! I'm having trouble with the link to "Big Gears for Any Engine", it appears as though it has been removed. I really need to get ahold of that article and get more educated. Maybe eBay? I also was pleased to see the side by side pictures of your '38 and '57 transmissions. (38-57_trans.JPG) Are there 6 pictures supposed to be there? Only one comes up for me.

My "custom" project is actually a Flathead powered '36 Ford in which I intend to install a Buick floor shift and Buick torque tube rear end. Maybe the first time this has ever been done? I want to keep the transmission as short as possible to minimize or eliminate the mods to the frame x member. The smaller 5 bolt tranny should easily handle a mildly modified flathead.

Sean, I sure appreciate you taking the time to help me out here. If anyone else has input, PLEASE keep me in mind.

Thanks, Bookertee (Jim)

[sean1997]

There is only one picture, I think the number refers to how many people have downloaded (viewed) it. If you go to google or ebay and search for "The Best of Hot Rod Magazine 1949-1959" you should find the book. The tailshafts grew over the years. In '38 they were very short, but by '57 they were very long. For the rear end, one thing to check is the gear ratio. Some manual trans cars had gear ratios in the 3.9 to 4.54 range, so you might want something different. In '57-'58 manual trans cars had 3.58 compared to 3.20 in automatic cars. See this thread for more info on gear ratios:

http://forums.aaca.org/ubbthreads.php/ubb/showflat/Number/439747#Post439747

[MrEarl]

TTT