Posted By: JackAttack 1959 3200 tranny type - Tue May 27 2014 12:43 AM
Is this casting number a Saginaw 4 speed? The side of tranny casting number is GM 3781980. It has a granny gear and wondering if there's a swap to eliminate granny and get better gearing for in town and highway use. It appears to be the original transmission. Thanks.
Posted By: Flxible Re: 1959 3200 tranny type - Tue May 27 2014 12:50 AM
you have the standard SM420 4 speed, usually folks just ignore 1st and use it as a 3 speed .... your choice is go with the original standard 3 speed, no granny, but still 1:1 high, or find an original style OD 3 speed, or switch to a modern OD trans .... or change the rear gears to the [sometimes] available 3.38 ratio

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