* 4L60E: This 4-speed automatic was very common.
* 4L80E: A heavier-duty 4-speed automatic, often found in models with larger engines or heavier towing packages.
* Manual Transmissions: While less common, some 1999 Silverado 1500s were available with 5-speed manual transmissions. The specific model number would vary.
To know for sure what transmission is in *your* specific 1999 Silverado 1500, you need to check:
* The vehicle's identification number (VIN): A dealer or online VIN decoder can provide detailed specifications.
* The sticker on the driver's side doorjamb: This sticker often lists options, including transmission type.
* The transmission itself: Look for markings on the transmission case. This is less reliable without expertise.
Without the VIN or other identifying information, it's impossible to definitively say which transmission your truck has.
