* Transmission type: The transmissions themselves are different designs. The 1995 likely has a 4L60E (or possibly a 4L80E if it's a heavy-duty model), while the 2003 likely has a 4L60E but with significant internal differences and likely a different computer control system. Even if the designation is the same (4L60E), internal components are not interchangeable.
* Computer Control: The 2003 transmission's computer interface and programming are vastly different from the 1995's. The 1995's system simply won't understand the signals from the 2003 transmission.
* Bolt Patterns and Mounting: While there might be some superficial similarities, the bellhousing bolt patterns and the overall mounting points are unlikely to be compatible.
* Output Shaft: The output shaft may have different diameters or spline counts, preventing it from connecting to the 1995's driveshaft.
In short, while they might look superficially similar from the outside, the internal workings and control systems are too different to make a direct swap feasible. You would need a transmission specifically designed for a 1995 Silverado.
