Hello Everyone,
I just stumbled on this post and wanted to add my two cents as this is an interesting topic. I own a 1970 W30 w/AC and I have TM 3:42 which my car came and to best of my knowledge was never messed with. I have the broadcast card as well. The vehicle was mfg last week of Oct '69 and the rear end has a D/C of K12 (Sept 12th 1969) from what I've been told, so in theory this would be consistent as original to my car. In High School I removed the original, put it storage and installed a 3:91 rear end from a wrecked 442, as I wanted to be quicker on the street, if you know what I mean....So I have my original 3:42 rear end, the 3:91 and also a complete W27 which I will install when I do a concourse restoration. This just adds to the mystery.....

 

Well,here's another example of the 3.42 with A/C in a 70 W-30. If you have the broadcast card,isn't the rear axle id code on it? Let us know what you have. Thanks for the info.

 

Hello,
No axle code noted on the broadcast card for my car, is there supposed to be one?
Jim

 

I'm not familiar enough with the cars with broadcast cards to know. Maybe somebody will see this that knows and will give some idea. I know it will not say the actual ratio but may have the TM code for the 3.42.

 

The broadcast card is from the body plant so I don't think the axle code should be there.

 

I do not recall an axle code any any of the broadcast cards I have

 

well Chad just posted a "Production B" card and it shows an axle code.

https://classicoldsmobile.com/forums...-w-30-a-2.html

 

Would the '70 p-o-p show the axle code? I know the earlier ones do and the later ones don't.

 

'68 was the last year the POP had engine, trans, rear (and more) info on the POP.

 

I am going to resurrect this thread because it has happened again. I bought a 70 442 Conv. 4 speed with A/C from a buddy who has owned it since the 70's It's a matching number car built in Linden,NJ. I have it in my buddies shop for some leak repair & exhaust repair. I went down to see what rear axle it had & I already knew it was a posi because of the tag. We got to cleaning and scraping and found the code-TM. This is the second car that I haver owned that has a TM code 3.42 rear axle which is supposed to be a no no. I went back to my buddy and asked him if he ever had the rear axle out or changed and his answer was no he hadn't. Here we go again.

 

And-you found the matching vin derivative on the trans on the passenger side of transmission..another anomaly..

 

Well that's debatable. With my research all I could come up with was the right side stamping. I asked the question here about the Lansing built cars stamping and all I got was ........crickets.

 

If the car hasn't been restored- i bet there is at least 1-2 build sheets to be found.

 

Our 70 W-30 with AC has the 3.23 posi that was in it. With the AC cars as built the 3.23 was the only option do to Oldsmobile pulley drive ratio as told to me by the dealer parts manager (Who use to race Oldsmobile). Having said all that, it was quite common for owners to swap out the entire differential for 3.42 or even 3.91 as in my case. When the group that I used to run with did this we would just remove the AC belt. 1 of the guys ( I will called him Randy ) didn't remove his belt on a night of racing at Orange County International Raceway and on the way home his AC compressor locked up on him.

I still have my spare 3.91 differential however I need a yoke for it after a hard 1st to 2nd shift twisted the driveshaft in half and broke the yoke while running in another car. The W-30 currently has the 3.23 gear differential back in it.