different automatic transmissions. From 1977 until 1980, the 3-speed THM200 was the sole transmission. From 1981 through 1990, the THM200-4R 4-speed automatic with overdrive was added, as GM added a lock-up torque converter and a 0.67:1 overdrive ratio. With the overdrive transmission, the Custom Cruiser drive with a numerically higher rear axle ratio for better performance, while offering improved fuel economy with the overdrive range In its final year of production, the second-generation Custom Cruiser marked the end of the Oldsmobile-produced V8 (formerly the "Rocket V8"). Shifting from its long-running practice of each division developing its own engines, during the 1980s, GM consolidated V8 production in non-Cadillac full-size cars towards Chevrolet and Oldsmobile, with the latter division developing diesel engines. Towards the end of the decade, GM phased out the Oldsmobile V8 family, as the 307 was the final engine produced by the company without fuel injection. After 1990, Oldsmobile would not have a division-produced engine; the only GM division-unique engine family developed since 1990 was the Cadillac Northstar (developed with some Oldsmobile and Pontiac applications). Oldsmobile diesel V8 For 1978, Oldsmobile introduced its first diesel engine, a naturally aspirated 120 hp 350 cubic-inch V8. For 1980, the V8 was retuned to 105 hp, remaining an option through 1985. Body In contrast to the 1971-1976 Custom Cruiser, Oldsmobile styled the 1977 Custom Cruiser as a station wagon version of the Delta 88, adopting its front fascia entirely. To distinguish itself from its nearly identical Buick, Chevrolet, and Pontiac counterparts, the Custom Cruiser was given its simulated wood design, with wood following the curve of the wheel wells. In a major departure from the 2-piece "clamshell" tailgate of its predecessor, the Custom Cruiser was fitted with a two-way tailgate; similar to configurations offered by Ford and Chrysler, the two-way tailgate opened to the side as a door or hinged down as a tailgate (with the rear window glass retracted). The third-row seat made its return, allowing for 8-passenger seating; to allow for production commonality on a single wheelbase, the Custom Cruiser was produced with a rear-facing third row seat (as were all full-size GM station wagons). Alongside all B-platform station wagons and sedans, the Custom Cruiser saw an exterior update for 1980, with wagons receiving a new front fascia. To aid aerodynamics and fuel economy the grille and front fascia were redesigned, with the headlamps mounted closer to the front bumpers.