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Very rare 1970 3.42 W-30 12-bolt Posi traction. This is from a one-owner 1970 Oldsmobile 442 W30 4-speed car. Although you could order 3.42 gearing on a regular 442, the W30 rear ends have different codes. "TM" rear axle code is stamped on the passenger side axle tube. "TM" code is W30/W31 ONLY. "402227" casting on housing denoting 1970 casting. Original owner re-ringed to 4.33 ratio. No brake hardware or drums. Seattle, WA. $2,500.
I’m interested in the rear end. I have a 1971 w30 442 4 speed. The build date is January. I’m wondering if since my build date is so early 1971 the TM code is still correct for a 71. I can’t find any info to help make a smart buying decision. Can you help. Thanks. Mark
I’m interested in the rear end. I have a 1971 w30 442 4 speed. The build date is January. I’m wondering if since my build date is so early 1971 the TM code is still correct for a 71. I can’t find any info to help make a smart buying decision. Can you help. Thanks. Mark
Hi mark. Sadly this rear end is incorrect for your car. The 1971 and 1972 442 W-30s used 10-bolt corporate (IE chevy) rear ends. They are still "TM" code for 3.42 posi (or "TO" 3.73), but otherwise they are different. This rear end is a 12-bolt "olds" rear end. It would fit and function fine in your car, but would be wrong from a restoration perspective. If you are going to spend good money on a rear end it would make sense to get the correct one especially for a car as rare as a 71 W-30 4 speed such as yours.
Thanks for the great information! At least a 10 bolt is more common and I have 2 choices! Even better. If you hear or see what I need please don’t hesitate to reach out. All the best. Markjnorris
The 1971 and 1972 442 W-30s used 10-bolt corporate (IE chevy) rear ends.
While they are similar,these are NOT chevy rearends; they are different as they use bolt-in axles and not c-clip retainers as used on Chevy rearends. The original rear from my car has a block O on the front sections where the axle tubes fit, which clearly indicates it is an Oldsmobile rearend. I have read on the forum that Buick rears were also used in this time frame.
I’ve just got a few things to get this 4speed W-30 convertible bright and right! His rear end with your help gets me that much closer. Thanks again!!! All the best. Mark
September 21st, 2019, 02:44 PM
