* Part-time 4WD: This system is engaged manually by the driver using a shift lever. It's intended for use primarily on slippery surfaces (snow, ice, mud). Driving with part-time 4WD engaged on dry pavement at higher speeds can cause damage to the drivetrain.
* Autotrac (Automatic 4WD): This system automatically shifts between 2WD and 4WD based on wheel slippage. It provides more convenience than part-time 4WD, but it's not as capable off-road as a dedicated part-time system.
To know *how* the 4WD on your specific 2001 GMC Jimmy works, you need to check your owner's manual. The manual will detail the system's operation, including how to engage and disengage 4WD, and any limitations. It will also tell you which type of 4WD system your Jimmy has (Part-time or Autotrac).
If you don't have the owner's manual, you can often find a digital version online through the GMC website or through a third-party site like repair manuals. Looking at the sticker inside the driver's side door jamb might also reveal information about your vehicle's drivetrain.
