1998 GMC Sonoma Owner's Manual - Page 85

REVERSE (R): back up, press the clutch pedal, To wait about six seconds, then shift into REVERSE (R). Then let up on the clutch pedal slowly while pressing the accelerator pedal. This light will show you when to shift to the next higher gear for best fuel economy. When this light comes on, you can shift to the next higher gear if weather, road and traffic conditions let you. For the best fuel economy, accelerate slowly and shift when the light comes on. While you accelerate, it is normal for the light to go on and off if you quickly change the position of the accelerator. Ignore the SHIFT light when you downshift. I NOTICE: Shift to REVERSE (R) only after yourvehicle is stopped. Shifting toREVERSE (R) while your vehicle is moving could damage your transmission. Use REVERSE (Rj, along with the parking brake, for parking your vehicle. I Shift Light T you have a manual f transmission, you have a SHIFT light. If you skip more than one gear when you downshift, you could lose control of your vehicle. And you could injure yourself or others. Don't shift down more than one gear when you downshift. f your vehicle has four-wheel drive and is equipped with a manual transmission, disregard the shift light when the transfer case is in 4LO. SHIFT 2-21