Jolly Green

Anybody know the options available for a 1968 Olds 442 rearend? Posi? Gear ratio, etc? My 442 has the 12 Bolt cover but I understand those can actually be 10 bolt diffs correct? Just wondering what I will find when I get home from Afghanistan and pop the cover to rebuild it. I am pretty sure, when I worked on it a few years ago, that when I spun one wheel, the other spun the opposite direction.

Dave Siltman

If that '68 was built in Canada (look for that on the data plate under the hood) it would've originally had a "C" (Chevy) type rear end. The options and possible variations would differ. Determine what style you have before you obtain any wrong info. or parts.

wmachine

Check the Chassis Service Manual and the Product Information Manual (aka Assembly Manual), both you'll find for FREE on Wild About Cars.

Wild About Cars. http://wildaboutcars.com. An information supersource, especially Oldsmobile. More Olds content than anywhere else on the internet and continuing to grow.
You'll find Chassis Service Manuals, Product Information Manuals (AKA Assembly Manuals), Inspector's Manuals, and other documents that will contain this and much much more.
Dealer Brochures, magazine ads and articles, and a home page for you online. You can even have your very own club there and a personal forum.
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rcorrigan5

There were two types of differentials in '68. One was the "O" axle with gear ratios of 2.56, 2.78, 3.08, 3.23, 3.42, and 3.91 in either an "open" or "anti-spin" version. There was also an "O" axle 4.33 gear in just the "anti-spin" version (I believe the 4.33 gears were dealer-installed). The other type of differential was referred to as the "C" axle and was used in Canadian built vehicles in gear ratios 2.56, 2.73, 3.07 and 3.31, in either "open" or "anti-spin".

There should be a two-letter or a letter-digit code on your axle housing that will tell you what gear ratio you have. Most of the time I've found it stamped upside-down on the passenger side forward.

Check the 7th figure in your VIN. If it is the number "1", your car is Canadian-built. If there is a letter in that position, your car was built in the USA and that letter will tell you which assembly plant built your car.

As "wmachine" said, a great place to go is www.wildaboutcars.com. There is a host of info at that site that you can view and download for free. Signing up is also free. I highly recommend it!

Randy C.
'68 4-4-2 convertible
'69 4-4-2 convertible
'70 GTO hardtop
'71 Corvette coupe