GM 25740120
Transmission Cooler

To replace the Auxiliary Automatic Transmission (AT) Oil Cooler, the following is done: detach the front air deflector, and then disconnect the auxiliary transmission oil cooler inlet and its outlet line. Next, you will have to remove the auxiliary transmission oil cooler mounting bolts and remove the auxiliary transmission oil cooler. To install, start by installing the auxiliary transmission oil coolers, making sure to observe the Fastener Notice in Service Precautions. Next, mount and tighten the auxiliary transmission oil cooler mounting bolts to a 6.5 Nm (58 inch lbs.). Then make a connection to the auxiliary transmission oil cooler outlet line and inlet line and reinstall a front air deflector. Finally, check on the fluid transmission level and examine the auxiliary transmission oil cooler for leaks.

You need to start by removing the Intake Manifold together with the water crossover before replacing the Oil Cooler and Oil Cooler cover. The first step is to detach the inlet fitting together with the outlet fitting from the Engine Oil Cooler while keeping records of the 4 seals' initial positions. Begin by taking off the Engine Oil Cooler lines running through the engine followed by the removal of Engine Oil Cooler inlet and outlet nuts and Engine Oil Cooler cover bolts. Remove the Engine Oil Cooler cover and the cooler itself to clean the mating surfaces of the cylinder block while inspecting the Oil Cooler design. Begin by installing the Engine Oil Cooler inlet/outlet o-ring seals before applying a 2 mm (0.08 inch) bead of gm p/n 12378521 (Canadian P/N 88901148) to the groove around the Engine Oil Cooler cover. Thread adhesive gm p/n 12345382 (Canadian P/N 109534382) should be applied to Engine Oil Cooler cover bolts prior to position its installation onto the engine. Start by affixing the Engine Oil Cooler cover bolts to their respective locations and tighten them to 20 nm (15 ft. Lbs.) using a sequence method. Install the Engine Oil Cooler inlet and outlet nuts while applying 30 nm (22 ft. Lbs.) of torque force. Use 4 new seals when installing the Oil Cooler inlet and outlet fittings to the Engine Oil Cooler. Both fittings need to be tightened to 30 nm (22 ft. Lbs.). You should first connect the Oil Cooler lines to the engine before completing installation with the water crossover and the Intake Manifold.

Begin the Auxiliary Automatic Transmission (AT) Transmission Oil Cooler replacement by removing the front air deflector followed by disconnecting the inlet and outlet lines. Start by removing the auxiliary transmission oil cooler mounting bolts before taking out the auxiliary transmission oil cooler. When installing the auxiliary transmission oil cooler begin by installing the auxiliary transmission oil cooler mounting bolts then torque them to 6.5 Nm (58 inch lbs.). Reinstall the front air deflector after you connect the auxiliary transmission oil cooler outlet line to its respective inlet line. Check the transmission fluid level and look for any signs of leakage on the auxiliary transmission oil cooler.

Remove the engine oil cooler from the engine and clean the cylinder block mating surfaces as well as the oil cooler itself.