Hello- I'm new to this forum and this will be my first post. I've read a ton on the topic of the w-27 rear end and I want to ask the experts...Is this original? I purchaesed the 12/27/2022 and I'm still going through her. It is a documented 1970 W-31 in which the bill of sales reflects the G80, G92 and W31 (Anti spin, 3:42 and Machine Package). Is this W-27 rear end the real deal? Thank you in advance.

 

Would the bill of sale not reflect an additional charge for W-27 if it had been ordered that way from the factory?

BTW, welcome to CO!

 

Does not look like it, a W27 rear has an aluminum center section. Your rear looks just to have an aftermarket cover.

 

The whole car has been under coated black. The part that beside the cover that should be aluminum was painted. The rear end has the 3 (on each side) pressed in stamped marks to marry the aluminum to the steel. The Machine packege was a way to add the aluminum cover into the packege cost. Car came from Canada, Thanks for welcoming me!

 

Welcome to classic olds. That is reproduction cover on a steel housing differential.

 

Seems it would be pretty simple to stick a magnet to the differential housing to see if it sticks.

 

Seems to me that the W-27 rear differential would have been noted on the order form as......W27.
Welcome to Classic Oldsmobile, by the way.

 

There is a casting number on the lower right front of the center section. That should be of some help identifying the rearend.

 

Trying to get the build sheet from GM. Some members have already jumped in offering assistance, Thank you! Will try the magnet trick, TY. Collecting as much intell on the car that I can.

 

Im leaning towards a big negative to the fact it's a original w27 cover. I read in two articles, which confused me, that when getting the machine package, that you could get the W-27 aluminum cover included. But the more I look into it it makes complete sense that it's a simple $57 add-on and it would be listed out on the bill of sale as w27 like everything else on the bill of sale. Just trying to make sense of the lack of information on the car that I have and what's on the car that's actual.


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That pretty much tells you the car was never ordered or delivered with a W-27 (Option W27).

 

It looks to be repro cover. Car was not a W27 production car.

 

Even if the car had the W27 originally, there is no guarantee it would still be there all these years later. I don't know what you paid for the car but if it had a W27 rear, the price would have reflected it. The price of these things is crazy.

 

It is definitely a reproduction cover on a steel housing.

 

No matter how you look at it it seems to be a very nice documented W-31.Enjoy the car.
Alain red W-31

 

Thank you for all your advice! Here she is with SSIs and with SSIIIs.

 

Absolutely!!!!

 

Super sexy ride!!!! Like the SSII better

 

Very nice!

Yeah, and as pointed out above, if it were a factory W-27 car, you'd likely be able to tell from the gaping hole in your bank account. Shouldn't make the slightest bit of difference in your ability to enjoy it, though!

 

Reproduction Cover, even original covers are expensive and difficult to find and the housing looks like iron. The casting number will confirm.

Documented W-31s are not easy to find. Congrats!

 

The one on the left is nos and the reproduction is on the right.

 

Thanks for that 👍

 

BTW, congrats on the Nuggets!

 

Drive the W-31 down to Iron Gate and I'll help you go through it on the lift.