To find the drain plug, you'll need to:
1. Identify the specific differential and transmission. Your Blazer's owner's manual will specify the type. The information is also often stamped on a tag on the unit itself.
2. Locate the differential: This is usually a housing at the rear of the vehicle near the axle.
3. Locate the transmission: This is typically a large casing between the engine and the differential (or transfer case in a 4WD).
Once you've identified the correct component (differential or transmission), look for the drain plug. It's typically a bolt on the bottom of the housing. It might be a round bolt head or a square one. It will likely be made of metal (often a different color than the housing), and may be slightly recessed.
Caution: Before attempting to drain any fluids, consult your owner's manual for specific instructions and torque specifications for the drain plug. Draining fluids requires careful attention to avoid spills and injuries. You may need to use a jack and jack stands to safely access the drain plugs. Wear appropriate safety gear.
If you're uncomfortable working under your vehicle, it's best to take your Blazer to a qualified mechanic.
