Transmission Oil Cooler

Replace the transmission oil cooler assembly, which cools the transmission fluid to prevent overheating and maintain proper transmission operation.

Warnings

Tools required

Parts

• Transmission oil cooler assembly × 1 — Use OEM Maserati part
• Transmission oil cooler lines O-rings/seals × 1 — Use OEM specification
• Transmission drain plug crush washer × 1 — Use OEM specification
• Coolant (if contaminated) × 1 — Maserati OAT Coolant
• Transmission oil cooler mounting bracket (if damaged) × 1 — Inspect and replace if necessary

Fluids

• ZF Lifeguard 8 — 10 qt
• Maserati OAT Coolant — 2 qt

Preparation

1. Park vehicle on level ground and engage parking brake
2. Allow engine and transmission to cool for at least 2 hours
3. Disconnect negative battery cable to prevent electrical issues
4. Raise vehicle and secure on jack stands at all four corners, ensuring adequate working clearance
5. Remove engine undertray and any protective covers to access transmission and cooler lines
6. Place large drain pan under transmission drain plug location
7. Verify replacement cooler matches OEM part number and includes all necessary fittings

Procedure

1. 1

   Drain transmission fluid
   Locate the transmission drain plug on the bottom of the transmission pan. Place drain pan beneath plug. Remove drain plug and allow fluid to drain completely (approximately 10 quarts). Inspect drained fluid for coolant contamination (milky appearance or pink/green tint). If contamination is present, transmission may require additional service. Install new crush washer on drain plug.
   Torque spec

   Drain Plug35 Nm (26 lb-ft)
2. 2

   Partially drain coolant system
   Locate coolant drain plug at bottom of radiator. Position drain container beneath radiator. Open drain plug and drain approximately 2-3 quarts of coolant to lower level below transmission cooler lines. This prevents excessive coolant loss when disconnecting cooler. Close drain plug when coolant level is below cooler connections.
   Torque spec

   Coolant Drain Plug15 Nm (11 lb-ft)
3. 3

   Locate and access transmission oil cooler
   The transmission oil cooler is typically mounted on the driver's side of the radiator assembly or integrated into the lower radiator tank on the Levante. Trace transmission cooler lines from the transmission (passenger side) forward to the cooler location. Remove any air duct work or plastic covers blocking access to the cooler and line connections. Take photos of routing for reinstallation reference.
   ℹ️Cooler location may vary slightly. Follow the hard lines from transmission to identify exact mounting point.
4. 4

   Disconnect transmission cooler lines at transmission
   Starting at the transmission end, locate the two transmission cooler line connections on the transmission case. Clean area around fittings to prevent contamination. Using appropriate line disconnect tools or wrenches, carefully disconnect both cooler lines from the transmission. Be prepared for residual fluid spillage. Cap or plug transmission ports immediately to prevent contamination. Label lines 'supply' and 'return' for correct reinstallation.
   ⚠Do not twist or bend transmission cooler lines excessively as they can kink or crack.
5. 5

   Disconnect transmission cooler lines at cooler
   Move to the cooler end of the lines. Disconnect transmission cooler lines from the cooler assembly using line disconnect tools. Some coolant and residual transmission fluid will drain from lines. Inspect line connections and O-rings for damage. If lines are hard-mounted, remove any clips or brackets securing lines to chassis or engine components.
   ⚠Inspect O-rings and sealing surfaces carefully. Replace all O-rings during reassembly to prevent leaks.
6. 6

   Disconnect coolant connections from cooler
   If cooler is integrated into radiator or has separate coolant connections, carefully disconnect coolant inlet and outlet lines using appropriate tools. Have drain pan positioned to catch coolant spillage. Loosen hose clamps and carefully remove coolant hoses, twisting gently to break seal. Inspect hoses for damage or deterioration.
   Torque spec

   Hose Clamps3 Nm (2 lb-ft)
7. 7

   Remove transmission oil cooler mounting bolts
   Locate all mounting bolts securing the transmission oil cooler to its bracket or radiator assembly. On the Levante, cooler is typically secured with 2-4 mounting bolts. Support cooler with one hand while removing final mounting bolt to prevent dropping. Remove all mounting hardware and carefully extract cooler from vehicle, maneuvering around any obstructions.
   Torque spec

   Mounting Bolts64 Nm (47 lb-ft)
8. 8

   Inspect and clean mounting area
   With cooler removed, thoroughly inspect mounting bracket and surrounding area for damage, corrosion, or coolant/fluid residue. Clean all mounting surfaces with appropriate cleaner. Inspect radiator (if cooler mounts to it) for damage. If any coolant/transmission fluid mixing occurred, flush affected cooling system passages. Verify new cooler matches old unit in configuration and port locations.
   ℹ️If coolant contaminated transmission fluid, consider flushing transmission cooling circuit and replacing additional fluid.
9. 9

   Install new transmission oil cooler
   Position new transmission oil cooler into mounting location, ensuring proper orientation and that all connection ports are accessible. Install mounting bolts finger-tight first to ensure proper alignment. Once aligned, torque mounting bolts to specification in a cross pattern if multiple bolts are present. Ensure cooler is secure and does not contact any surrounding components that could cause vibration or chafing.
   Torque spec

   Mounting Bolts64 Nm (47 lb-ft)
10. 10

    Reconnect coolant lines to cooler
    If cooler has coolant connections, install coolant hoses onto cooler inlet and outlet ports. Ensure hoses are fully seated on barbs/fittings. Install new hose clamps if originals show wear, positioning clamps properly over hose and barb. Torque hose clamps to specification, being careful not to overtighten and damage hoses.
    Torque spec

    Hose Clamps3 Nm (2 lb-ft)
11. 11

    Reconnect transmission cooler lines to cooler
    Install new O-rings on transmission cooler line fittings, lubricating lightly with clean transmission fluid. Connect transmission cooler lines to new cooler assembly, ensuring 'supply' and 'return' lines are connected to correct ports (refer to photos taken during disassembly). Push fittings fully home until they click or seat completely. Tug gently to verify secure connection.
    ⚠Reversed cooler lines can cause transmission overheating and damage. Verify correct routing against service documentation.
12. 12

    Reconnect transmission cooler lines to transmission
    At transmission end, install new O-rings on line fittings and lubricate with clean ZF Lifeguard 8 fluid. Connect both cooler lines to transmission ports, ensuring proper seating. If lines use threaded fittings, torque to specification. If quick-connect style, ensure they click into place. Reinstall any line support brackets or clips to prevent vibration and maintain proper routing.
    ℹ️Proper line support is critical to prevent fatigue failure from vibration.
13. 13

    Refill coolant system
    Locate coolant expansion tank and remove cap. Using funnel, add Maserati OAT coolant to replace amount drained (approximately 2-3 quarts). Fill to proper level marking on expansion tank. Reinstall expansion tank cap. Start engine and allow to reach operating temperature while monitoring for leaks at cooler connections. Top off coolant as needed after air purges from system.
    ⚠Do not remove expansion tank cap when engine is hot. System is pressurized and can cause burns.
14. 14

    Refill transmission fluid
    Locate transmission fill plug (typically on side of transmission case). The 8HP70 transmission requires filling from underneath with special equipment. Using transmission fluid pump and appropriate fill adapter, pump ZF Lifeguard 8 fluid into transmission until fluid begins to drip from fill hole. Transmission should be at operating temperature (85-95°F oil temp) for proper fill level. Install fill plug with new washer if applicable.
    ⚠Transmission fill procedure on ZF 8HP70 requires specific temperature range for accurate level. Use scan tool to monitor transmission fluid temperature during fill.
    Torque spec

    Fill Plug35 Nm (26 lb-ft)
15. 15

    Test system and check for leaks
    With vehicle still raised and supported, start engine and allow to idle. Shift transmission through all gear ranges (P-R-N-D-S and back to P) while stationary, pausing 2-3 seconds in each position. This circulates fluid through cooler circuit. Visually inspect all connection points at transmission, cooler, and coolant connections for leaks. Check fluid levels again and top off if necessary. Test drive vehicle through all gears and monitor transmission temperature to ensure proper cooling.
    ⚠️Keep hands and tools clear of moving components. Ensure parking brake is engaged and wheels are chocked.
    ℹ️Transmission temperature should stabilize below 200°F during normal driving. Overheating indicates improper installation or additional issues.

Reassembly

1. Reinstall all protective covers and engine undertray panels removed during access
2. Torque all fasteners to specification using cross-pattern where applicable
3. Ensure all cooler lines are properly routed and secured with clips to prevent chafing or vibration contact
4. Verify all fluid levels are correct after test drive and top off as necessary
5. Reset any transmission adaptation values using appropriate diagnostic tool if available
6. Reconnect negative battery cable and verify no warning lights are present

Verification

• Check all connection points for signs of fluid or coolant leakage after test drive
• Verify transmission fluid level is correct at operating temperature using fill plug check method
• Confirm coolant level is stable in expansion tank after system has cooled
• Test drive vehicle and verify smooth transmission operation through all gears
• Monitor transmission temperature gauge or scan tool data to confirm temperature remains in normal range (160-200°F)
• Inspect transmission fluid appearance - should be clear red/pink with no milky appearance indicating coolant contamination
• Re-inspect all connections after 50-100 miles of driving and verify no leaks have developed
• Verify no transmission warning lights or codes are present after repair

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