Guys, I am doing a bit of a research project on the 71 Olds "OW" trans usage on our Buicks. My question is this.. near the center of the tag, a 71 Buick TH 400 id tag would say "71 B" followed by the julian build date. I am sure that the OW trans, when used in a Buick was vin code stamped with a "4OHXXXXXX", the "4" representing the Buick Motor Division. This stamp was no doubt applied during chassis assembly or shortly before, so the Olds trans was stamped as a Buick. My question is, since is it likely that Hydramatic attached the trans tag at their factory, did they in fact know it was going to be used in a Buick, and then create the id tag with a "71 B" , or does it reflect the "71 O" that would be there if it were used in it's intended application. I am leaning toward the idea that it would be "71 O" but would like some input from you guys with 71 OW transmission that may still have the tag in good shape. I have a couple OW transmissions in the building, but all the paint is gone from the id tags. Here is a picture for reference.. this is a 70 BB tag, I have circled the area in question. Thx JW
Jim, From what I recall seeing, it would have a large "O" on one end and "W" on the other. Would then have 71W on the tag. The first letter on the tag is for the division (A=Cadillac, B=Buick, C=Chevrolet, O=Oldsmobile and P=Pontiac) and the 2nd is the trans model. The tag would be blue in color for 1971. These were literally Oldsmobile transmissions put in a Buick. The Vin would be 41H000000 etc. on the stamping of the trans to identify the vehicle. 4=Buick 1=71 and H=Flint (or whatever plant it was built at. Someone with an OW in their car might have more information, but I think the above is the way it will turn out. Regards, Mark
Yes.. I get caught up in the 70 cars when talking stamped Vin's, since they are so prevelent.. your of course correct, it would be 41HXXXXXX on a 71 Stg 1 trans.. Interesting .. a "W"... I was under the assumption that this silkscreened letter would have been an "O" for olds, since all the Buick transmissions had a "B" in that location after the year.. Thanks Mark Anyone else? JW Here is an OW tag pic that I found, but can't make out what is after the "71" near the center of the tag... but now that you say it, looks like it certainly could be a "W" there. Any info on the meaning of that letter?..
Jim, The letters were assigned by each division and identified what components such as valve bodys, clutches, governors and tail lengths were be used in each trans. One divisions letter codes were not the same as another. B = Stage 1 in Buick, but was used to identify a full size Pontiac trans. From what I can tell, the Olds W trans was similar to the Stage 1 in Buick, possibly a W-30 unit. Pontiac had Q & R models which were for high performance models. So, there is no special significance for B model units. Ron Sessions tran book does a good job of identifying which letter code was used by a division. Am pretty sure that Larry has posted a chart in a thread somewhere. Hope this helps, Mark
Yes Mark, I have the sessions book.. very dog eared after all these years. I am afraid my question was not clear enough.. I am aware of the calibration/hard parts differences in relation to the trans code. Sorry for the confusion on that. My concern is the letter after the year designation that is silkscreened on the tag.. as pictured below and indicated by the blue arrow. Every Buick tag I have ever seen has a "B" there.. and " I can get my head around that".. it's the "W" for an olds that brings on the confusion..
Also.. while I have you Mark.. Any info that you could share concerning what appears to be the julian build date after the "70 B" on the tag above would be helpful, as well as any info you might have in the relationship this date would have to the serial number stamped on the lower right. Reason I ask is that we had assumed that the "293" on the tag would be the 239th day of 1969 for this particular trans, but I have seen a few 70 BB transmissions with numbers over 400 in that location. I have developed a couple of theories, and looking for more info to prove or disprove them. First would be that when they identified day number 1 on the julian calander, it was signified by a "100" stamp, vs a "001".. so the transmissions would be date coded 100-465.. I have seen a couple 445 numbers stamped there, as I have about a dozen or so examples to look at in the shop here. Now I believe I have seen julian numbers below 100 in the past, but I don't have a trans case in the shop with that number below 100.. in fact most of them are more than 200, and once we started discussing this triva, well, you know how those discussions go.. sooner or later you just have to figure it out.. so you can sleep at night.. ou: My next theory is that this is actually a "day of production", regardless of any calander.. example above would be the 293rd day of TH 400 production of that year. Therefore if they went 500 days in a row building 400's, they just kept counting till the line was switched over to build something else. Yes, triva for sure, but after a while with boards like this, we run out of questions.. JW
Jim, Am 99.999% certain that the silk screened letter is always the trans model and not the division. Can't get at my pile of TH400's right now as they are in my storage shed. I have one from a 69 Sportwagon 400 in my basement (don't ask) that definitely has 69W silk screened. The ones I have seen all have the model of the trans after the year. A Sportwagon 400 is a BW model. So, 69W would be correct. The pic you show for a 70 Stage 1 would be correct at 70B. A GS455 (I know I have several stored) would be 70A for the model BA trans. If you have worked on mostly 70 Stage 1 units, they would be 70B. I also have a few 70 Riv units that definitely have 70T on them for the model BT trans and 70 Electra ones that have 70C on them for model BC. Once I can get at them, I can take some digital pics and post. The date code is very interesting. Code on the 69 Sportwagon trans is 365. In theory, that should be 12/30/68 (leap year). The Ron Sessions book confirms this. However, you are correct. One should have seen codes of 002, 015 or 099 and I can't recall ever seeing dates below 100. You may be correct in thinking they start with 100 up to 465. Chassis manuals I have call this a Date Build Code and not Day code. So, 100 could be Jan 1 etc. Giving some thought, allowing a 5-6 month lead time to have units built for production, April 10 would be about date 200. Late December would be up to date 460 or so. The April date would be good for cars built in September and the December date for cars built in June. January to March dates would not likely happen as that would be the model year changeover for the next year. Production would run April-December with build dates of 200-460 which falls in line with your theory. Hope we are not overthinking this. Maybe Duane has more info on this build date question. Mark
Ok Mark, now we are on the same page with the letter code.. it's the second letter of the trans code, not the first. That helps a lot, thanks.. I have done many, many Buick TH 400's, but 90% of them had a tag that the paint was no longer ledgible (or possibly I wasn't paying attention back then.. ) That clears the confusion up for me, thanks for the input Mark. I hear Duane is writing a book on this stuff, that would be some great info to have handy, as there is only so much stuff that will fit in my head at any given time, and I tend to forget things that I once knew.. Either that, or I am getting old.. one of the two.. On the date code.. that 293 coded tag, belongs to board member Glen Biggers, for a car that was built the second week of Dec, 1969. JW
Quote: My next theory is that this is actually a "day of production", regardless of any calander.. example above would be the 293rd day of TH 400 production of that year. Therefore if they went 500 days in a row building 400's, they just kept counting till the line was switched over to build something else. Jim, I worked at Hydra-matic Division in Ypsi from 1976-1986 on the 400 as well as 200,425,325,and finally 125 lines. The assembly lines were dedicated to one of these transmissions and did not switch in and out. When I hired in the 2 lines that ran 400's never ran any other type trans the entire time of my employment. They changed often during a shift however as to which division the tranny was being built for i.e. Buick, Olds, Rolls Royce, Jag, whoever needed a run. Production was usually around 800 to 1200 per shift. Hope I understood the theory right and don't appear to be rambling.
Eddie, Yes, I suspect that could be the hole in that theory.. those lines ran 400's.. thousands of them for all the diffrent applications, and it never built anything else.. that makes sense from a production standpoint. Mercy.. 1200 a shift.. no wonder these things grow on trees.. Can you fill us in on any of the tag info? Know anyone who worked there whose responsiblity it was to stamp them.. Any other cool info that can only come from someone who worked there? Or better yet.. pictures? Thanks :TU: JW
Perhaps someone in the union local for that plant will know the retirees who in tern will know who had the job in question.
The tags were applied in button-up area which was after the test room sector. As I recall they came ready to install and were not manufactured in the production area of the plant. The cases were stamped with letters that applied to the division which it was built for and the particulars of the innards of the tranny, i.e. which forward/direct clutch set went in or which valve body was installed and which convertor etc. After the trans was assembled it went into the test room where it was attached to a real gas engine and went through a series of runs including passing gear and detent as well as regular upshift under load. If (and only if) it passed test did it go to button up where the pan and tags were applied before shipping. I remember that area well because in the summer they would open the old hanger doors (which appeared as walls when closed) to help cool off that part of the plant. The B-24 Liberator was built there during WW II and rolled of the assembly line out those same hanger doors and onto Willow Run Airport. Some of the old trolley machinery that the planes were carried on was still up in the ceilings when I worked there. Very cool place. It was the largest plant under one roof in the world at one time. Over a mile long and 1/2 mile wide.
Wow, and you just turned 39.......sheesh hate to see when you turn 50, you won't know your name! :Brow: Wow, where do you live? You sure have some funny looking trees....must have HUGE limbs! News to me.....finding a shortshaft TH400 in the local FL yards has been an exercise of futility. They are getting very rare since most cars in the yards are now FWD crap. Most of the time, I find the TH400 shortshafts in 73-77 Pontiac Grand Prix models. Otherwise, most cars that have the TH400 are the longer shaft outputs, 6 and 9" for full size models.
That's why I have my "stash" of TH400's. Somewhere about 25-30 at present. Mostly 1969-73 long and short tail Buick units (BA, BC, BU & BT). When I moved in 1999 I GAVE away 25-30 of them ranging from 1971-77 long tail ones. Listed them for sale first at $25 each..........no takers. So, the fellow who paint my Sportwagon took them away. Stored somewhere in case he ever needed them. Rarely see them in yards here too. Bet there are a few guys who are sorry they didn't buy some at that $25 each. ou: Mark
Understanding the date Ok, so if I get this, it means that 293 would be Oct. 20, 1969. The 445 stamp would then mean March 21, 1970? Since production continued on the TH400 over year end, the date would not reset to 001 on January 1? It would just continue until the line was switched over to either a TH350 or whatever? uzzled: uzzled: uzzled: Help me out here. Thanks, Mark
Mark, I guess, from what Eddie said, that line never switched out to anything else, it always built 400's.. So that date code theory is pretty much dead, at least for the reasoning that they changed the line out.. Also he seems to indicate that the tag was produced at a vendor.. which I had suspected, and that would be why there is stenciled information, and stamped information on the same tag. I had assumed that the tag was stamped at the hydramatic plant. Am I incorrect in this assumption Eddie? JW
I need to go water my 400 tree... :laugh: Still plenty of them left out here in "flyover land" guys.. Short tails are getting a little scarce, and 8 bolt cases are real hard to find, but later models are still around. JW
From the best of my memory the only thing stamped at our plant was the case itself up on the bellhousing area and all the little parts like valvebodies and such. Though it is possible that stamping may have occured in button up area.
