🔧 Terrain - Automatic Transmission Fluid Change (Drain & Fill)

This service replaces a portion of your Terrain’s automatic transmission fluid by draining the pan and refilling with fresh fluid. It helps shift quality and transmission life, especially if the fluid is dark or has a burnt smell.

Difficulty Level: Intermediate | Estimated Time: 1.5-3 hours

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⚠️ Safety & Precautions

• Work on a level surface; the fluid level check is very sensitive to vehicle angle.
• Use jack stands; never rely on a floor jack alone.
• Transmission fluid and exhaust parts can be hot—wear gloves and safety glasses.
• Keep the engine running only when the vehicle is safely supported and wheels are chocked.
• No battery disconnect is required for this service.

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🔧 Required Tools

You'll need the following tools for this repair:

• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks
• Safety glasses
• Nitrile gloves
• Drain pan (at least 10-quart)
• Socket set (metric)
• Ratchet (3/8")
• Torque wrench (in-lb and ft-lb capable)
• Fluid transfer pump (specialty)
• Trim clip tool
• Flat screwdriver
• Shop rags
• Brake cleaner spray
• Scan tool with transmission fluid temperature PID (specialty)
• Infrared thermometer

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Automatic transmission fluid (DEXRON-VI) - Qty: 6 quarts
• Transmission drain plug gasket/washer (if equipped) - Qty: 1

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📋 Before You Begin

• Park on level ground, set the parking brake, and place wheel chocks at the rear wheels.
• Plan to check the fluid level at operating temperature; a scan tool reads the transmission’s temperature sensor (most accurate).
• Tip: Remove the fill plug first. This prevents getting stuck with an empty transmission you can’t refill.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Warm the transmission

• Drive the Terrain for 10–15 minutes to warm the fluid.
• Park on a level surface and keep the engine off for now.

Step 2: Raise and support the vehicle level

• Use a floor jack (rated 3-ton minimum) to lift the front at the proper jack point.
• Set the vehicle onto jack stands (rated 3-ton minimum).
• Confirm the vehicle sits level front-to-rear and side-to-side.

Step 3: Remove the lower splash shield (if equipped)

• Use a trim clip tool and flat screwdriver to remove clips/screws.
• Set the shield and fasteners aside.

Step 4: Locate the fill plug and level plug

• The fill plug is used to add fluid.
• The level plug (also called an overflow/check plug) sets the correct fluid level; when the transmission is at the correct temperature, excess fluid drips out of this hole.
• Place a drain pan (at least 10-quart) underneath the transmission area.

Step 5: Remove the fill plug first

• Use the appropriate socket set (metric) with a ratchet (3/8") to loosen and remove the fill plug.
• Wipe the area with shop rags.

Step 6: Drain the old fluid

• Use the appropriate socket set (metric) and ratchet (3/8") to remove the drain plug.
• Let the fluid drain into the drain pan until it slows to an occasional drip.
• Clean the drain plug and sealing surface using shop rags and brake cleaner spray.
• Reinstall the drain plug and Torque to 12 Nm (106 in-lbs).

Step 7: Refill with fresh DEXRON-VI

• Insert the fluid transfer pump (specialty) into the fill port.
• Pump in DEXRON-VI until you’ve added roughly what drained out (commonly ~4–5 quarts on a drain & fill).
• Reinstall the fill plug finger-tight for now (you may need to reopen it for final top-off).

Step 8: Circulate fluid through the valve body

• Start the engine with your foot firmly on the brake.
• Slowly move the shifter through P-R-N-D and back, pausing 3 seconds in each position.
• Return the shifter to PARK and keep the engine running.

Step 9: Check transmission fluid temperature

• Use the scan tool with transmission fluid temperature PID (specialty) to monitor transmission fluid temperature.
• If you don’t have scan data, use an infrared thermometer on the transmission pan as a rough estimate. Tip: Scan tool is best.
• Target temperature for level check: 85–95°C (185–203°F).

Step 10: Set the fluid level using the level plug

• With the engine running and temperature in range, place the drain pan under the level plug.
• Use the appropriate socket set (metric) and ratchet (3/8") to remove the level plug.
• Correct level behavior:
  • If fluid drips in a thin stream then slows to a steady drip, the level is correct.
  • If no fluid comes out, add fluid through the fill port using the fluid transfer pump (specialty) until it begins to drip from the level hole.
• Reinstall the level plug and Torque to 12 Nm (106 in-lbs).
• Reinstall the fill plug and Torque to 12 Nm (106 in-lbs).

Step 11: Reinstall the splash shield

• Reinstall clips/screws using the trim clip tool and flat screwdriver.
• Lower the vehicle using the floor jack (rated 3-ton minimum).

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✅ After Repair

• Test drive 10–15 minutes and confirm normal shifting.
• Park on clean pavement and check for leaks around the drain plug, fill plug, and level plug.
• Dispose of used ATF properly (most auto parts stores accept it).
• Tip: Recheck for leaks the next day.

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💰 DIY vs Shop Cost

Shop Cost: $220-$420 (parts + labor)

DIY Cost: $45-$90 (parts only)

You Save: $175-$330 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 1.5-2.5 hours.

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🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.

Assumption: Your Terrain uses the common GM 6-speed automatic with a drain plug and side level-check procedure; plug locations can vary slightly by transmission variant.