* 4L60E: This 4-speed automatic transmission was the most common.
* 4L80E: This 4-speed automatic transmission was used in some models, usually those with heavier-duty options or larger engines.
To know for sure which transmission is in a specific 1999 Tahoe, you'd need to check the vehicle's identification number (VIN) or look at the transmission itself. The transmission type is often stamped on a tag on the transmission case.
