Transmission fluid is the most commonly deferred fluid service on the average car, and the consequences of indefinitely deferred service are among the most expensive mechanical repairs an owner will face. An automatic transmission rebuild or replacement costs $3,000 to $6,000 on a mainstream car and significantly more on European or luxury vehicles. A transmission fluid service costs $100 to $250. The return on the maintenance investment, expressed in avoided repair costs, is among the highest available in automotive ownership.

Three engineers at Lamborghini — Gian Paolo Dallara, Paolo Stanzani, and Bob Wallace — built the Miura’s chassis on their own time, without official company authorization, because they believed that a mid-engine sports car was the right direction and that the best way to convince Ferruccio Lamborghini was to show him one rather than explain it to him. They were correct. Lamborghini approved the project. Bertone’s Marcello Gandini, 26 years old, styled the body. The result was unveiled at the 1966 Geneva Show as a rolling chassis and sold as a complete car the following year.

The Land Rover Defender V8 answers a question that nobody strictly needed to ask: what happens when you put a supercharged 5.0-liter V8 producing 518 horsepower into a car that can also ford rivers, climb gradients that defeat other off-road vehicles, and carry a family of five across terrain that requires disconnecting the front anti-roll bar and deploying a low-range transfer case? The answer is that it works, and it works in a way that is not obviously coherent but is undeniably entertaining.

The cooling system is among the most neglected maintenance areas on the typical family car, which is why coolant-related failures account for a disproportionate share of roadside breakdowns and a significant portion of preventable engine damage. The system is invisible in operation — the coolant temperature gauge sits at normal, the heater works, and there is no obvious sign that the coolant circulating through the engine has degraded to the point where it is no longer doing its job adequately.

The Toyota GR86 costs $32,000 in base form and provides a quality of driving engagement that cars costing three times as much work hard to replicate. This statement should require extensive qualification, and it does not. The GR86 is a rear-wheel-drive, naturally aspirated sports car weighing 2,822 pounds with a 228-horsepower flat-four that is intended not for straight-line performance but for the kind of driving that roads and tracks reward in direct proportion to the driver’s willingness to use the entire rev range and manage the car at the limit of adhesion.

The case against the current Porsche 911 GT3 is that it is too good. The controls are too precise, the chassis too composed, the engine too willing — it conceals how fast it is going and how close to its limits you are, which means you can arrive at speeds that require considerable competence to manage without having received adequate warning that they were approaching. This is not a criticism that would survive scrutiny in court, but it is the honest assessment of what makes the GT3 different from sports cars that communicate their limits more generously.

The Chevrolet Corvette E-Ray is the first Corvette to use all-wheel drive and the first to use a hybrid powertrain, two statements that would have been inconceivable to anyone familiar with the Corvette’s sixty-year identity as a rear-wheel-drive, naturally aspirated (or supercharged) American sports car. The E-Ray adds an electric motor to the front axle — drawing from a 1.9 kWh battery that is too small for any meaningful EV range but large enough to provide front-axle torque on demand — while retaining the 6.2-liter LT2 V8 at the rear.

The doors open upward because they had no choice. The 300 SL’s tubular space frame — the structure that gave the car its extraordinary stiffness-to-weight ratio and allowed the lightweight body to be hung around it — ran high along the sills, creating a structural barrier too tall for conventional door openings. Rudolf Uhlenhaut’s engineers solved the access problem by hinging the doors at the roofline. The solution that looked like showmanship was engineering necessity, and the car that looked like an Italian dream was actually a German calculation.

The AMG GT 63 four-door coupe occupies a position in the Mercedes lineup that required a new category rather than a modification of an existing one. It is not a sedan. It is not a GT car in the traditional two-seat sense. It is not a crossover despite its elevated roofline providing more headroom than a conventional saloon. It is a 630-horsepower, four-seat automobile that covers the distance between major European cities in a way that is faster, more comfortable, and more dramatic than any alternative in its price class.

The timing belt connects the crankshaft to the camshaft or camshafts, synchronizing the opening and closing of the engine’s valves with the movement of the pistons. In an interference engine — the design used in the majority of modern cars — the pistons and valves share the same space at different times, with the timing system ensuring they do not occupy it simultaneously. When the timing belt fails, synchronization is lost. The pistons and valves meet. The damage is immediate, severe, and entirely preventable.