"18" Transmission questions...

PeteVS

PeteVS

Well-known member
I started cleaning up a three speed today. Serial number implies that it's from a '35. Question is, "What's the machined recess in the bottom of the case for?" It looks to be about 6" behind the drain plug. Also, will this case take a 29 tooth cluster gear? If not, when did the 29 tooth (pickup) start? Thanks!!

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What is the number at the back of the case? Should be a 48 or 78. Does it have a full rib in the bottom? I put a set of 29 tooth gears in a 1936 case, it was a 48.
 
If it's a '35 case then the number at the back of the case should be 48-7006. This is not easy to install the 29 tooth gearset from pickups and heavier sedans. Can be done by installing the main gear without the bearing at first. Again not easy. If you are planning on a 9" or 10" clutch, they're just a good as the 78 style case, restoration not a factor. The 78 cases take the 29 tooth set without any installation acrobatics, but are a few bucks more money. The above information is as good as the information you posted. Like computers: Garbage in... Good luck: Fred A
 
The case has a rib on the bottom. There's a pocket machined into the rib towards the back. I thought the part number was 18-7006, but I'll have to look again tomorrow and also clean up the "pocket" area and get a better look. Thanks guys!
 
Not sure about what the pocket is but like Fred said, you do have to put it together without the bearing on to get past the cluster gear but I have done it twice now and it does work. The number above the inspection cover will be an 18 number but the number at the back where the cross shafts go in will tell what it is.
 
Gonna try to post multiple images here. Wish me luck!

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This is the serial number that I take to be 18-1616330 which should be a '35. Right?

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This is the part number, which looks like 18-7006 to me, but if someone says it's 48-7006, I guess I could see that too.

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Finally, the belly of the beast. Bottom rib goes to the drain plug. But, what's the machining towards the back? Also, taper from flange to case is constant without the "big clutch" straight portion, making it an "18." But on a '35?
 
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The 48- case was not necessarily used on Job 1 for 1935... probably there was, like with alot of things, a transition period?
 
Looks like an 18 case to me, no zerks for the clutch shaft and the funny machined spot on the back/bottom of the case. 18 case would be right for '34, as stated they could have some left over and use into '35...

Will
 
Huh, never saw an 18 case I guess but the number is for sure an 18. I have a case that has a full rib going all the way to the back and it's a 48, according to Mac van pelt, he says it has to be a 78 case but clearly the number is a 48 so I think Ford did some changes between years back then and the parts books don't show it. I think you could get a 29 cluster in that case. I am not positive though.
 
One last question...

One last question- This transmission has the "vertical" single detent shifter top, which I understand is typical of '35. Should I be able to bolt on a '32 thru '34 "leaning back" shifter? Forks will work, etc? As a matter of fact, will the "double detent" forks work with an earlier top? I have SO MUCH to learn...
 
I think the slider gear (first/reverse) changed in '35 and takes a wider fork than '32-34. So no '32-34 shift tower on '35 gears. I would recommend keeping things together as much as possible with the early gearboxes. You can mix & match some but it requires a lot of experience and access to spare parts.

"Double detent" has to do with the locking mechanism on the shifter shafts - not the forks themselves. And it generally refers to the 81A-7222 shift tower casting. But there are double detent tops with small forks ('38) and the later 91A front fork. Forks have to match the slider gear and synchronizer.

If you are interested in these things I would highly recommend Mac VanPelt's book, which you can purchase here:

http://www.vanpeltsales.com/FH_web/flathead_home.htm

Mac usually reads these threads and hopefully will get us back on track if I gave you any bad info. :)

Will Kimble
 
Got Mac's book last week. Have had a couple of these transmissions for a few years now (a couple of them for a lot of years) but this is the first time I've gotten into any of them. This particular trans I have absolutely no idea what it came out of. It's got the '35 serial number on it but it's been painted this light turquoise. It must have a history, but what's been done or swapped? No idea!
 
Will's advice is pretty much right on. We have found some funny examples on Ford transmission parts that were marked one way and very obviously stood out as another spec. I have a case in the shop that most definitely has an early 1937 serial number, but also is definitely a 48 series case. Ford was known for using up previous model year parts in early production for the next year.

If you have the upright style shifter tower (68-7222 or 81A-7222) you will want to stay with the '36 and later gears. The 32-35 slanted shifter tower must go with the 32-35 gears in my opinion.

Color of the gearbox means nothing. They've all been repainted various times in their careers. Match up the gears you want to use. Match the shifter tower and forks to those gears.
 
Bruce Lancaster said:
The 18 style cases will have the uninterrupted taper from engine flange back to case, 48 style and up have a nearly straight area for about an inch and slightly moved cross shaft/different fork, all to clear the bigger clutches.
Old post here summarizes trans part spotting: http://www.jalopyjournal.com/forum/...&highlight=transmission+prices+1939&showall=1
Click to expand...

I believe as Bruce mentioned in his post, the 18- case will not be as deep as the 48- case in the clutch bell area. A 9" clutch & PP will work well but if you want a 10" clutch, some grinding for clearance on the inside of the bell will be required. JM
 
I'm working on a '34 case with it's original gears now and have been reading the '49 chassis parts book I have (orange cover). It list parts specific to the '32 to '34 transmissions ("B" designation) as well as "40" and "48" designation for '35 for the cluster, synchro hub and shifting forks. The 28 tooth gear on the cluster seems to be narrower on the "B" and the synchro is a different length and the forks are slightly different. My point being, keep the gear set together and take some measurements and compare to Ford's listed dimensions to determine exactly what you have, stuff tends to get mixed up over the years!
Paul J.
 
There are two groups of the early gears, do not remember differences but they are called out in bulletins. I do not think there would have been any problem with Ford continuing to make early case transmissions with either case or the clutch bits for use in the cars made with 9" plates, and I'm sure the available 11" use in cars would have been very rare.
Keeping gear sets together will really help in maintaining sanity on any of these!
Bell difference is really in extra width, keeping it full width rather than tapered for about the first inch. Once you have seen the difference it is easy to spot. They also dropped the clutch cross shaft very slightly and altered fork to make some space.
I have never done this, but people who have say that installing a 10" clutch in the early case requires only minor grinding on the bosses for shaft in there.
 
Got a little deeper into the subject transmission today and noticed that although the case is an "18", the clutch fork is a "48."
 
The 48-7515 became the '28-48 replacement, following the A and B 7515...difference is a tiny shift in a curved contact. But assume nothing unless you saw the complete number...I had one of each side by side from comparison, and found a "48" on the early one! Flipped it over and found the complete early part number...the "48" was apparently just a forging number or such, and was not actually a 48 prefix!
 
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