* 4L60E: A four-speed automatic transmission. This was the most prevalent option.
* 4L80E: A four-speed automatic transmission, typically found in models with larger engines (like the 8.1L V8).
To know for sure which transmission a specific 2001 Suburban has, you'd need to check the vehicle's documentation (owner's manual, sticker on the doorjamb) or the vehicle identification number (VIN).