Yes, there is a difference in time dilation when a clock passes in front of us compared to when it's moving away from us. This difference is a consequence of the theory of relativity, specifically the effects of relative motion and gravitational fields on the passage of time.
According to the theory of special relativity, time dilation occurs when two observers are in relative motion to each other. If a clock is moving relative to an observer, the observer will measure the clock to be ticking slower than their own stationary clock. This effect is known as time dilation due to relative velocity.
On the other hand, in the theory of general relativity, time dilation also occurs in the presence of gravitational fields. Clocks in stronger gravitational fields, where gravity is more intense, will appear to run slower compared to clocks in weaker gravitational fields. This effect is known as gravitational time dilation.
When a clock passes in front of us, the time dilation experienced by the clock will be a combination of both the effects of relative motion and gravitational fields. As the clock approaches us, its motion relative to us will cause time dilation due to relative velocity. However, if the clock is also moving through a gravitational field (such as that of the Earth), there will be an additional gravitational time dilation effect.
When the clock is moving away from us, the time dilation effects will still exist but may be different in magnitude. The relative motion will still cause time dilation due to relative velocity, but the gravitational time dilation may be altered depending on the change in the strength of the gravitational field as the clock moves away.
In both cases, the specific magnitude of the time dilation effects will depend on the relative velocities, distances, and gravitational fields involved. However, it's important to note that these effects are typically extremely small and only become significant under extreme conditions, such as near the speed of light or in the vicinity of massive gravitational objects.