You have a Saginaw 4 speed. It was used in late 1970's and 80's GM pony cars like the Chevy Vega, the OHC six Pontiac Firebird, and a few other mid-size GM factory hotrods with 4 and 6 cylinder engines. Any factory pony car service manual from that era should have repair instructions, and there are a bunch of them available at reasonable prices on Ebay. It's a weak sister compared to the earlier Muncie trans, even though the Muncie had an aluminum case. A former GM research engineer I worked with in the Tennessee state trade school system was on a team that tried to beef up the heat treating of the gears to work behind high horsepower V8's, and they didn't have a great deal of success.
Jerry
