* Reduced highway speed: Overdrive is a higher gear ratio that allows the engine to run at lower RPMs at higher speeds. Without it, the car will struggle to maintain highway speeds and will likely be very noisy and use much more fuel.
* Increased engine strain: The engine will be working much harder at any given speed, leading to increased wear and tear.
* Poorer fuel economy: Expect drastically reduced gas mileage.
* Lower acceleration: Acceleration will be sluggish, especially uphill.
In short, while it's *drivable*, it's not ideal or recommended for anything beyond short, low-speed trips. The lack of overdrive will severely impact performance, fuel efficiency, and engine longevity. The problem should be investigated and fixed.
