🔧 Grand Cherokee WK - Automatic Transmission Fluid Change

This job on your Grand Cherokee WK’s 8-speed automatic is not like an engine oil change. The transmission is “sealed,” needs special fluid, special tools, and must be filled at a specific temperature.

If you are very new to DIY, strongly consider having a professional do this, or have a helper with experience.

Difficulty Level: Advanced | Estimated Time: 3-4 hours

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⚠️ Safety & Precautions

• ⚠️ Always support the Jeep with jack stands; never rely only on a jack.
• ⚠️ The exhaust, transmission, and fluid can get very hot; let the vehicle cool before working.
• ⚠️ Transmission must be level when checking / setting fluid level or it will be wrong.
• ⚠️ You must use the correct Mopar 8&9 Speed ATF; do not substitute generic ATF.
• ⚠️ You need a scan tool that can read live transmission fluid temperature; guessing the temperature can damage the transmission.
• ⚠️ Work in a well-ventilated area and keep fluid off skin and eyes.
• ⚠️ Disconnect the negative battery cable if you will have the ignition on for a long time while underneath.

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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, set of 4)
• 🛠️ Wheel chocks
• 🛠️ Socket set (8mm–19mm metric)
• 🛠️ 10mm socket
• 🛠️ 13mm socket
• 🛠️ Ratchet (3/8" drive)
• 🛠️ Torque wrench (5–80 ft-lbs range)
• 🛠️ Torx bit set (T25–T40)
• 🛠️ Hex/Allen bit set (metric)
• 🛠️ Transmission fluid hand pump (fits gallon/liter jugs)
• 🛠️ Transmission fill adapter for 8-speed (specialty)
• 🛠️ OBD2 scan tool with live data (trans temp) (specialty)
• 🛠️ Plastic trim clip removal tool
• 🛠️ Drain pan (at least 10-quart capacity)
• 🛠️ Shop rags
• 🛠️ Parts cleaning brush
• 🛠️ Brake cleaner spray
• 🛠️ Safety glasses
• 🛠️ Nitrile gloves
• 🛠️ Funnel (small tip)

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• 🔩 Mopar 8&9 Speed ATF - Qty: 6–7 quarts (drain and fill)
• 🔩 Automatic transmission pan gasket - Qty: 1
• 🔩 Automatic transmission filter - Qty: 1
• 🔩 Transmission drain plug washer/seal - Qty: 1
• 🔩 Plastic underbody shield clips - Qty: 4–6 (as needed)
• 🔩 Brake cleaner (aerosol) - Qty: 1–2 cans
• 🔩 Shop towels/absorbent pads - Qty: 1 pack

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📋 Before You Begin

• Park the Grand Cherokee WK on a level surface, engage the parking brake, and chock the rear wheels.
• Make sure you have your scan tool set up and know how to view Transmission Fluid Temperature in live data.
• Gather all tools and parts so you are not crawling out from under the vehicle repeatedly.
• If desired, disconnect the negative battery cable using a 10mm socket to prevent accidental starts.
• Plan to keep the Jeep level on jack stands when you refill and check the fluid level.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Safely raise and support the Jeep

• Use the floor jack to lift the front of the Jeep at the front crossmember jacking point.
• Place jack stands securely under the front pinch welds or frame points, then lower the Jeep onto them.
• Repeat for the rear so all four wheels are off the ground and the vehicle is level.
• Verify stability by gently rocking the Jeep; it must not move.

Step 2: Remove any underbody shields

• Use a plastic trim clip removal tool to remove plastic clips from the front underbody shield, if equipped.
• Use the appropriate socket (often 10mm) to remove any small bolts holding the shield.
• Lower the shield and set it aside where it won’t get stepped on.

Step 3: Locate the transmission pan, drain plug, and fill port

• The transmission pan is the large, roughly rectangular metal pan under the middle of the vehicle.
• The drain plug is on the bottom of the pan; it may use a hex/Allen or Torx head.
• The fill plug is usually on the side of the transmission case (or in a fill adapter port in the pan area) — you will attach your fill adapter here.
• Identify fill plug before draining.

Step 4: Loosen the fill plug first

• Use the correct socket, Torx, or hex bit and a ratchet to carefully crack the fill plug loose, but do not remove it fully yet.
• This confirms you will be able to refill the transmission before you drain it.
• Snug it back lightly so dirt does not fall in.

Step 5: Drain the old transmission fluid

• Place the drain pan under the transmission drain plug.
• Use the correct socket or hex bit with a ratchet to slowly remove the drain plug.
• Allow the fluid to drain completely; this can take several minutes.
• Inspect the fluid color and smell; dark or burnt-smelling fluid indicates it was overdue.
• Remove and replace the drain plug washer/seal if separate from the plug.

Step 6: Remove the transmission pan

• With the drain plug out and most fluid drained, use a socket set (usually 10mm or 13mm) and ratchet to remove all pan bolts.
• Leave two bolts loosely threaded at opposite corners to hold the pan while the last fluid drips.
• Support the pan with one hand and remove the last bolts.
• Carefully lower the pan; there will still be some fluid inside.
• Pour the remaining fluid into the drain pan; note how much total came out (use the quart marks).

Step 7: Clean the pan and magnets

• Use brake cleaner and a parts cleaning brush to clean the inside of the pan.
• Wipe the magnets clean; a light grey paste is normal wear material.
• Dry the pan thoroughly with shop rags.
• Install the new pan gasket on the pan, aligning all bolt holes.

Step 8: Replace the transmission filter

• Locate the transmission filter mounted to the valve body above where the pan was.
• Use the correct socket or Torx bit to remove the filter screws, if used.
• Pull the filter straight down; some fluid will still drip out.
• Compare the new filter to the old one to confirm it matches.
• Install the new filter by pushing it into place and tightening any mounting screws with the ratchet and correct bit.
• Tighten filter screws to manufacturer spec (do not overtighten).

Step 9: Reinstall the transmission pan

• Lift the cleaned pan with new gasket into position against the transmission.
• Hand-thread all pan bolts to avoid cross-threading.
• Use a ratchet and correct socket (10mm or 13mm) to snug bolts evenly in a crisscross pattern.
• Use a torque wrench with the same socket to tighten each bolt evenly.
• Torque to 8–10 Nm (71–89 in-lbs) in a crisscross pattern unless your service information states otherwise.

Step 10: Reinstall the drain plug

• Install the cleaned drain plug with new washer/seal by hand.
• Use the correct socket or hex bit and torque wrench to tighten.
• Torque to 8–10 Nm (71–89 in-lbs) unless otherwise specified by service info.

Step 11: Perform the initial refill (engine off)

• Install your transmission fill adapter (specialty) into the fill port or pan adapter.
• Attach the transmission fluid hand pump to your ATF container.
• Pump in roughly the same amount of fluid you drained out (usually about 4–5 quarts) with the engine off.
• Do not over-tighten the adapter; just snug with the correct wrench/socket if required.

Step 12: Prepare for final level check

• Ensure the Jeep is still level on jack stands.
• Reconnect the negative battery cable with a 10mm socket if you disconnected it.
• Connect your OBD2 scan tool to the diagnostic port under the dash and open live data to view Transmission Fluid Temperature.

Step 13: Warm the transmission and cycle gears

• Start the engine with the brake pedal pressed.
• With the engine idling, hold the brake and move the shifter slowly through each gear (P-R-N-D and manual +/- if equipped), pausing 3–5 seconds in each position, then return to Park.
• Repeat this 2–3 times to fill the circuits with fluid.
• Watch the scan tool and wait for transmission fluid temp to reach about 30–40°C (86–104°F).

Step 14: Set the final fluid level at temperature

• With the engine idling, parking brake applied, and wheels chocked, go under the Jeep carefully.
• Place the drain pan under the fill adapter area.
• Loosen the fill adapter plug or level plug with the correct socket or hex bit.
• If no fluid drips out at the specified temp, use the hand pump to add ATF in small amounts until a small steady stream begins to flow out.
• When a small solid stream turns into a thin drip, the level is set.
• Install and tighten the fill/level plug with the correct socket or hex bit and torque wrench.
• Torque to manufacturer spec (typically around 8–10 Nm).

Step 15: Reinstall underbody shields and lower the Jeep

• Reinstall any underbody shields using the original bolts with the correct socket and your ratchet.
• Press new or reused clips back in with the plastic trim clip tool if needed.
• Use the floor jack to raise the Jeep slightly, remove the jack stands, and lower the Jeep to the ground.

Step 16: Final checks

• Wipe any spilled fluid off the transmission and surrounding areas with shop rags and a little brake cleaner.
• Take a short, gentle test drive (5–10 km), cycling through all gears.
• Check for leaks around the pan and plugs afterward.
• If shifting feels abnormal or rough, or you see leaks, stop and recheck levels or consult a professional.

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✅ After Repair

• Start the engine and confirm smooth engagement when shifting from Park to Drive and Reverse.
• Use the scan tool to confirm transmission fluid temperature behaves normally when driving.
• Inspect under the Jeep over the next few days for any fresh fluid spots.
• Dispose of old ATF properly at a recycling center or service shop; do not pour it on the ground or in drains.

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💰 DIY vs Shop Cost

Shop Cost: $350–$600 (parts + labor)

DIY Cost: $120–$220 (fluid, filter, gasket, small supplies)

You Save: $230–$380 by doing it yourself!

Shop labor rates typically run $100–$150/hour. This repair takes a shop about 1.5–2.0 hours.

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🎯 Ready to get started?

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