I'm not sure how far this covers your application, but my '78 AMC Tech manual shows three manual tranmissions, and two 4-speeds. The 4-cylinder 4-speed is called a Model HR1. Metric standards, meaning bolts, etc. The other 4-speed is a SR4. The SR4 is an all-aluminum case, whereas the HR1 has a cast iron case, and aluminum tailshaft housing. There's an ID tag on the left side ( drivers ) where the tail shaft housing is bolted to the main body of the trans. Other specs for the HR1 : Gear oil is SAE 80W-90 Gear Lubricant, API grade GL-5 Capacity - Model HR1 is 1.13 liters, or 2.4 pints USA In answer to your question of OD, no, it's just a plain 4-speed, NOT an overdrive transmission. The Overdrive trans has a button on the shift lever to activate the OD....I have a friend with a '75 Gremlin with 3-speed OD, so know what one looks like. :) My Gremlin GT, 1978, has a 4-speed, and I've heard it's not as reliable as the older 3-speed was. Some weakness in the design, it's not a hi-po tranny for slamming gears, apparently! LOL. Anyway, I suspect your trans may follow mine, but not exactly sure. If you check the ID tag on your transmission, you can find out ( if the tag is still there ) if it's an HR1 or not. I have other reference books, I may can find something for the Spirits, but would help to know the year of your car. :) Later, Jerry casper Virginia also at - Gremlingts@xxxx [Non-text portions of this message have been removed]