Help Needed Decoding a GM PartsWiki List

[Gromit]

Need help understanding something about the structure or design of those archived GM Parts lists that are available on gmpartswiki dot com (Which are excellent by the way)..

Please see image of one such page attached from a 1970 Chevy Truck steering column parts list.

For example, looking at the parts group 4.012; the first part is #3873136; "Control Lever Housing"

There is no confusion there of course - that part is obviously for a 1966 Series 20 (except D-D)

But what about the second part number (#3902564).

Does the list of other vehicle types above that number go with the first part number or the second?

Because if you look closely, there is no comma after the first vehicle description, but there are commas after the following vehicle descriptions, implying that they would go with the second part number.

But the other way would make sense too; as in; why not list the part and then all the vehicles...Hopefully I am not the only one confused

In other words, does the 1967 Series 10-20 (exc. D-D) use a #3873136 Control Lever Housing, or does it use a #3902564 Control Lever Housing?

By the way, I have no idea what a "D-D" is that they refer to; though I'm pretty sure that they don't mean "Daily Driver"

[Redline novdog]

The vehicles that part fits are above the part number.3873136 only fit the 1 application. I worked at both a Chevy and GMC dealerships in the '80s in the parts dept.Those old parts books were a pain to decipher

[bruceman1968]

D-D=Dubl Duti=Double Duty = Forward Control Chassis
There are abbreviation pages in the catalog you referenced(72 TL), page 78 to 80.

[Gromit]

Decipher - that is the perfect word for it...

Some people are probably wondering why I am asking about which line item goes with which vehicle; etc. as if it only matters for this one part number in my example..

But actually as most of you know the entire several hundred page parts list (and probably many others like it on gmpartswiki as well) is structured the same confusing way - rhetorically I ask myself why in the heck would GM not just insert one simple line feed between the parts to denote the next part number? Waste of paper?

Anyway, now that we all know, (thanks to you) that the list of vehicles is above the part number; I can finally now figure out my list of needed parts.

Thank you; and here is that same photo as before but now with highlighting showing how the parts number column relates to the vehicle type column; Thank God - I was at wits end with this one..flipping back and forth it was about to drive me berserkers

[Gromit]

D-D = Double Duty - I wouldn't have guessed that I must admit.. so it was one of those forward control step vans that folks use for food trucks these days...like in the attached photo I hope

Live and learn; thank you for taking the time to reply - every time I encounter some element that I don't understand in the GM parts list it just contributes to that general feeling of unease as if I may be missing something important.. and I start to think - oh my God, am I going to have to finally give in and call "The Guy"?

But after all it is not so bad; because in a way all of us and 67-72chevytrucks.com are collectively "The Guy" so no shame for me there; and 67-72chevytrucks.com is a friendly and totally rational site thanks to the efforts and vigilance of the site moderators.

[Redline novdog]

Good luck,take your time, and have fun! I never totally got it down. It's a little different with an angry farmer standing in front of you cussin' because his truck is broke down. LOL