Select-O-Speed (SOS) Quick ID, ORC vs DDC

KCM

Member
Hi there,

Was wondering if there is a quick way to ID whether a SOS has an over-running clutch (ORC) or a direct-drive clutch (DDC) by looking at the transmission. Any visual ques?

Searched the archives and a couple people said that if the housing part number is six digits and starts with a 3, then it has the ORC and if the number starts with C0NN or C3NN, it has a DDC. Is this correct? The New Holland parts catalog shows the same C3NN part numbers for both versions, and it says the DDC started in January 1963 which would mean the C0NN (1960 part number) would not have the DDC.

Any input appreciated.
 
The part number in the parts book is just that, a part number. It helps the dealer find the correct part for a particular application. It may or may not be close to what the raised casting number on the part is.

The raised casting number on the transmission housing and other parts are not the part number. They are a code that lets the Ford engineers keep track of design changes in the castings. Several casting changes may have been made to a part over the years while the part number remained the same or close to the original, so only the last one or 2 letters may have changed with the part number where the first 2 changed with the casting number.

Unfortunately they used similar coding methodologies for both the part numbers and the casting code numbers, so lots of folks think they're related, and sometimes the two numbers are close and sometimes they have no apparent relationship to each other.

From what I've read from others here, if it's got a CxNN casting number then it should be the later DDC model, and if its' got the 312xxx casting number then it's the older ORC model.

The first 2 characters of a part number are the decade and year within the decade that they first started using that part number in production. The first 2 characters of the casting code, on the other hand designate the decade and year within the decade of when that casting was designed.

The C0NN casting number just means that the casting was designed in 1960. It may be that they were working on the DDC transmission for a few years before they actually released it to the public, and the very first casting design from 1960 hadn't needed to be changed, but once they released it in 1963 they found something that required a design change to the casting, hence the C3NN casting numbers came out, but they were both DDC models with a C3NN part number because that was the first year it was used in production.
 

Yep! Look above and behind the inching pedal. A 312259 casting # should be the ORC. A C0NN or C3NN-7006-B should be the DDC.

I have run across one 312259 casting in my life that had the DDC installed and appeared to be factory that way.
 
Keep in mind when looking at casting numbers, that the number itself does not mean the year it was cast. Something starting with CONN could have been used for 3 straight years. It only gives you a rough idea.

Also, a bunch of castings could have been made in 1960, and then machined and assembled over the next few years.
 
Anyone have a simple explanation of the difference between
the two clutches and how they might differ from the usual
clutches in 4 or 5 speed transmissions?

Larry, I got the Case pin for servo #3 and will be attempting
the replacement soon. You said you had to cut the pin to size,
and I was wondering how one measures the length. Do I drive
it in and then trim off the exposed part? Also, do I need to
remove the servo to drive out the old and in the new, or can I
leave it in place and just remove the interlock cover.

Thanks for your help...
 

It's not too tough to do with the servo in place. If you got an other than OEM pin it may be long enough that you need to trim it. It's been awhile but I believe I trimmed it to length before driving it in.
 
It is my understanding that an overrunning clutch only "grabs" in one direction, sort of like a ratchet, so when the tractor's going down a hill it can go faster than the engine would be driving it on flat ground at a given rpm, which can lead to a runaway situation on a steep hill. The ORC S-O-S transmissions would still limit forward speed on a downhill in certain gears because the ORC only came into play when the number one servo was in one of two possible states. Someone else will probably chime in with the info on whether it would overrun when the number 1 servo was pressurized or whether it was when it was not pressurized, but I haven't memorized that part of the design.

A direct drive clutch is just that, direct, like a standard manual transmission clutch, so when it's engaged the engine will not only drive it forward, it will also limit the forward speed in a down hill situation.
 
Thanks for the input. What confuses me is this. With Ford part numbers, the first letter indicates the decade and the following number the year when the part was given the part number, and usually put into use. But the New Holland parts catalog states the DDC was used starting January 1963, which makes sense with the C3NN part number (1963), but C0NN (1960) would be before that date so theoretically would not indicate a DDC. I suppose the part could have been designed in 1960 for the DDC, but not actually used until 1963, but that"s a pretty big spread in years. Or maybe the New Holland catalog date is wrong for the DDC implementation.
 
(quoted from post at 22:23:14 04/11/13) Thanks for the input. What confuses me is this. With Ford part numbers, the first letter indicates the decade and the following number the year when the part was given the part number, and usually put into use. But the New Holland parts catalog states the DDC was used starting January 1963, which makes sense with the C3NN part number (1963), but C0NN (1960) would be before that date so theoretically would not indicate a DDC. I suppose the part could have been designed in 1960 for the DDC, but not actually used until 1963, but that"s a pretty big spread in years. Or maybe the New Holland catalog date is wrong for the DDC implementation.
Read Sean's first post again. I think you're still confusing a [b:ca873e1b3b]part[/b:ca873e1b3b] number
and its meaning with the [b:ca873e1b3b]casting[/b:ca873e1b3b] number.
Other than that I can't help much. I bought my first SOS last fall.
It does seem that I heard something about a different shape in the case,
might find something on that in the archives too.
 

Two quickie things to look for are drain plug and slanted flat surface on the right side of the cover. The early ones did not have them, later ones did.
 
(quoted from post at 22:23:14 04/11/13) Thanks for the input. What confuses me is this. With Ford part numbers, the first letter indicates the decade and the following number the year when the part was given the part number, and usually put into use. But the New Holland parts catalog states the DDC was used starting January 1963, which makes sense with the C3NN part number (1963), but C0NN (1960) would be before that date so theoretically would not indicate a DDC. I suppose the part could have been designed in 1960 for the DDC, but not actually used until 1963, but that"s a pretty big spread in years. Or maybe the New Holland catalog date is wrong for the DDC implementation.

The C0NN casting number just means that the casting was designed in 1960. The design could have been finished and the designs filed with their records department on 12/31/60, and then they could have started using that casting to build transmissions as early as May or June of 1962 for tractors they would be building in August of 1962, which was about when they started making the new 1963 model year tractors, but since they were officially 1963 model year tractors, the part number would have started C3NN, not C2NN. So that's a spread of only about a year and a half between designing the casting and starting to build transmissions using that casting. I figure in reality it was probably somewhere in the 1.5 to 2 year range. That makes sense to me if they wanted to build some DDC transmissions to field test the new design before they started rolling them out to customers, especially after the black eye that they had already taken from rushing the first S-O-S design out the door.
 
KCM , 312259 Transmissions are OVER RUNNING CLUTCH in the 1959-1962 Red and Gray Ag tractors and Red and Buff Industrial tractors unless as Larry has said it was a Dealer Warranty Modification to a DIRECT DRIVE CLUTCH which there was a few done that way . C0NN7006B Transmissions are DIRECT DRIVE CLUTCH which Ford started installing in the NEW 1962 FORD BLUE and GRAY tractors in AUGUST of 1962 , which again there is not a lot of them more common is the LATER REVISION C3NN7006B DIRECT DRIVE CLUTCH Transmission which was installed in the 1963-1965 tractors . I have been working on S-O-S 'S for over 30 years and own all casting number trans. in the original tractors that they were installed in from the factory and speak regularly with the Ford tractor engineers that were there when they were new and are still around today . Thanks Tony
 
For anyone interested??? I have a parts tractor with a non-working SOS. If any one needs parts i would like to sell. Thanks Jim in FL --No-Advertising-in-Forums
 
Hello Sean , The C0NN7006B transmissions were installed in the 1962 BLUE and GRAY TRACTORS built in AUGUST of 1962 until Dec. of 1962 and they were sold as 1962 tractors(since there was only 5 months of 1962 production that is why there is only a small amount of C0NN Trans.'s around versus the C3NN Trans. which had a three year 1963-1965 plus warranty and over the parts counter sales) they were not sold as 1963 tractors until Jan. of 1963 , it is the same as Ford selling the the 1963 1/2 Galaxie 500 not a 1964 Galaxie 500 or the 1964 1/2 Mustang not a 1965 Mustang that's the way they did it back then not the way they do it today where they sell cars 2014 cars in 2013 . Just as in Mid Year 1954 Ford brought out the 600 / 800 tractors during NAA production and sold them as 1954 tractors not 1955 tractors . Thanks Tony
 
Hello Royse , It does not make any difference between Part Numbers and Casting Numbers they both are identified the same way . The prefix c0nn means 1960 tractor , c3nn means 1963 tractor , b9nn means 1959 tractor NN is always tractor the first two are the year always . 7006 is transmission in car , truck , tractor it makes no difference . 6015 is engine block in car , truck , tractor it is always engine block . Example D2NL6015J IS A 1972 INDUSTRIAL 172 4 CYLINDER ENGINE BLOCK CASTING NUMBER . Thanks Tony
 
Thanks for that explanation Sean. I have the ORC and many
steep hills here so you may have just saved my life...
 
(quoted from post at 09:51:23 04/12/13) Hello Royse , It does not make any difference between Part Numbers and Casting Numbers they both are identified the same way . The prefix c0nn means 1960 tractor , c3nn means 1963 tractor , b9nn means 1959 tractor NN is always tractor the first two are the year always . 7006 is transmission in car , truck , tractor it makes no difference . 6015 is engine block in car , truck , tractor it is always engine block . Example D2NL6015J IS A 1972 INDUSTRIAL 172 4 CYLINDER ENGINE BLOCK CASTING NUMBER . Thanks Tony

Tony, You have a lot of knowledge, and have helped me and many others, but I think you've got the information about the casting codes incorrect. If a casting code of C0NN means a 1960 tractor, then why do the 1962 S-O-S tractors have a casting code of C0NN on their transmissions? Shouldn't the casting coed on those be C2NN then? You just got through explaining that the C0NN transmissions were used on 1962 tractors didn't you?

My 1973 4000 has casting codes of various years and even a couple of different decades on all of the different major components. My transmission, which has the same 1973 serial number and production code stamped into it as the number on the foil sticker under the hood, has a C7NN casting code, while my engine has a D0NN casting code, yet my tractor is a 1973, and the transmission and engine are both original. The production codes stamped into every major component match the numbers on the foil sticker, yet the casting codes on the various components indicate different years.

I have seen explanations on the web from former Ford engineers that the first 2 characters in the casting codes designate the decade and year within that decade that a particular casting was designed, not when a particular machine was made or when a particular part was cast. A particular casting design might have been used for many years in a row, so it will show up as the same casting number on machines of many different years.
 
It makes total sense that they would have redesigned the casting back in 1960 to build some research and development models for the DDC before going into full production in 1963. Don't know why that didn't occur to me. Guess I'm used to the car part numbers where the decade and year usually refer to the first model year the part was used. I'm sure there was more development time allowed on the SOS DDC, especially after their ORC debacle. Thanks Sean.

This has been an interesting thread. Didn't think it would create so many responses. Thanks everyone.
 
Hello Sean , Thank You , but the casting number and part number info is correct . The C0NN code was used because there was no update or revision until after 1962 . There could be some C2NN codes on other parts less visible then the common blocks , trans. , rear axles we speak of most often but every piece has a casting number(there is C0NN, C3NN, &C5NN casting on Sherman parts)Yes C0NN codes are on the 1962 Blue and Gray tractors but not the Red and Gray ones . If you look at the 310835 and 310837 4 speed and 5 speed trans. cases for the 01 series tractors there is no change from 1958 - 1965 , yet 801 rear axle center housings go from 310363 to 312480 to C0NN4024F , and I know the 310 to 312 was a Metal change from Pearlitic to a Malleable Steel as were 24" wheel centers going from 311701 to a B9NN1036A casting number were steel related because of cracking problems as were the rear axle housings . Casting numbers changed when a casting was revised or updated for some reason . Sometimes the revision was the same year as the original casting or not until two or three years later , so sometimes the prefix changes and sometimes only the suffix changes . Example the C0NN7006B DDC Trans. case has no drain underneath the case but C3NN7006B does have a drain plug under the case , without having all of the original Ford Blueprints I don't know of any other differences but there may be . Example B9NN6015B Block gas or diesel 1959 tractor factory installed spin oil filter adapter , C0NN6015C block gas or diesel 1960 tractor factory installed spin on oil filter adapter , C0NN6015J Block gas or diesel block is now cast for spin on oil filter and used past the end of tractor production in Dec. 1965 . Finally the rest of what you said is also correct which is just what I trying to explain . Thanks Tony
 
Tony,

Sorry for the confusion. I looked back and read your post a couple of times until it made sense.

I knew what the codes mean. The C at the beginning means the decade of the 1960's, and the 0 means the "0" year within the decade, or 1960. And the first N means that it was designed for the tractor division and the second N means that it was designed by the tractor division. The C means the decade.

When I read your statement the first time:

The prefix c0nn means 1960 tractor

I thought that you were saying that anything that has a casting number starting with c0nn had to be on a 1960 tractor, when in reality you were just saying the c0nn casting prefix can be broken down to the c0 meaning 1960 and the NN meaning designed by the tractor division for the tractor division.
 
OK- now lets throw a monkey wrench in the whole "engineering/part#" debacle. Ford auto castings used engineering numbers to indicate the first year a part was used... but they also date coded their castings to clarify when they were cast at the foundry, thus indicating what year they were used. A D0AE block may have a date code of 2C26... which means it was cast in '72 (2), March (C), on the 26th day. Does the tractor people do the same thing? Most date codes looked like a cast in tag with two fake looking screw heads cast with the tag, none of which were removable. Let's hear some responses on this theory. By the way, they didn't use an upper case I for date codes for obvious reasons- it can be confused with a 1.
 
i just got a select o speed and was brush cutting, it stop moving forward. could you please tell me what might be the problem with it. i also have tried to locate the seriral number and have not found it. i did find a number off the transmission case 312259 thanks for any information.
 

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