Why your 1966 mustang get into drive?

A 1966 Mustang wouldn't "get into drive" on its own. It requires a driver to shift the selector lever on the steering column or floor (depending on the transmission type) into the "Drive" position. If a 1966 Mustang *appears* to be going into drive without driver input, there's a serious mechanical or electrical malfunction. This could include:

* Transmission linkage problems: The linkage connecting the shifter to the transmission could be broken, bent, or improperly adjusted, allowing the transmission to shift unexpectedly.

* Transmission internal failure: Problems within the transmission itself, such as a faulty shift mechanism or worn parts, could cause unintended shifting.

* Vacuum issues (if automatic): Automatic transmissions in 1966 Mustangs relied on vacuum for some functions. A vacuum leak could cause erratic shifting.

* Electrical problems (if automatic): A malfunction in the electrical components controlling the transmission could lead to unintended shifting.

* Damaged or improperly installed shifter: A worn or incorrectly installed shifter could allow the transmission to accidentally move into drive.

In short, a 1966 Mustang doesn't magically go into drive. If it's happening, it needs immediate professional attention from a mechanic specializing in classic cars. Driving a car with this problem is extremely dangerous.