One exchange starter motor part number fits all 1800 engine types. Volvo advertising in the 1960s promoted the dependability of the 1800's ignition system. The ignition system was identical to the system found on the 140 and 120. A complete tune-up would include a new set of contact points, a condenser, a rotor, a cap and four spark plugs. Most 1800s came equipped with the M-41 four speed plus overdrive manual transmission through 1969.
Part numbers are substantially different between the two gearboxes.
A steering column-mounted lever engaged the overdrive when an 1800 was cruising in fourth gear. Both transmissions have an overdrive unit that requires fluid and filter checks. Replacement of the overdrive solenoid is sometimes needed. A rubber transmission mount located on the rear bottom of the transmission and attached to a frame crossmember is a candidate for replacement on high-mileage 1800s. Separate parts are available for rebuilding purposes.