Well, first, they're ALL 240's. The generic term ... "2" series car, "4" cylinder engine. Originally, traditional Volvo designation, a "242" is a 2-door, a "244" is a 4-door, and a "245" is a wagon (5-door). Early cars offered a 6-cylinder, so they're "260's" but we won't talk about them...
If you refer to them as simply a 240, it's helpful to others to call it a sedan or wagon (this is frustrating in classified ads... I KNOW it has power locks, I want to know if it has a TRUNK or a HATCH!)
In the early '80s, they started to drop the "24_" designation and simply started referrring to the trim level, i.e. "DL" or DeLuxe, "GL" or GrandLuxe.

It's perfectly ok to call it a 240 Wagon, a DL wagon, a 245, or a 245DL.

The shifter arrangement is a normal (geared) 4-spd transmission, with a 2-speed overdrive unit mounted to it's output shaft. The overdrive is turned on electrically, and interlocked with 4th-gear. You have to either flip a switch on top of the shifter (early cars) or push a button (marked 5, on later cars) to engage overdrive.

The transmission is next to indestructible, and the overdrive, while not unbreakable, is quite cheap to rebuild in the event of any trouble.
Rob Bareiss, New London CT