The topic of power flushing vs draining and refilling the transmission has been debated until both sides are blue in the face. We don't advise power flushing for various reasons, including 1) on the advice of our transmission expert, 2) it requires specialized equipment that most DIYers do not have access to, 3) it risks dislodging and moving particles on transmissions with many miles, 4) it's a relatively expensive operation, and 5) it requires a skilled technician for the process to be performed correctly. There are many industry experts on either side of the fence, but none can argue that dropping the pan, replacing the filter, and refilling the transmission with new fluid is not beneficial towards prolonging transmission life.
The 47RH, 47RE, and later 48RE automatic transmission found in Dodge Cummins applications also require periodic band adjustments. For more information, see: 47RH/47RE/48RE transmission band adjustment procedures.
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• Place a suitable oil drain container below the transmission.
• Remove all but (2) of the transmission pan bolts using a 13 mm socket; leave (2) bolts near the center of the pan on opposing sides.
• While holding the transmission pan firmly against the transmission, loosen the remaining transmission pan bolts 1/2 to 3/4 out. Carefully lower one corner of the transmission pan so the fluid can drain.
• Remove the transmission pan entirely and drain the remaining fluid into the oil drain container. Discard the transmission oil pan gasket; the gasket is NOT reusable.
• Locate the transmission filter. Remove the (3) bolts securing the filter to the valvebody using a T25 Torx driver, then remove and discard the transmission filter. Note that a significant amount of fluid will drain once the filter is removed.
• Thoroughly clean the transmission oil pan, including the inspection magnet. Ensure that all debris, dirty fluid, gasket material, clutch material, and other contaminants are removed. The transmission pan gasket mounting surface must be clean and smooth to ensure a leak-free fit.
• Install the new transmission filter in reverse order. Torque the Torx bolts to 35 in-lbs (inch pounds).
• Align the transmission pan gasket on the transmission oil pan, then position under the transmission and install the bolts hand tight.
• Snug all transmission pan bolts down then torque to 156 in-lbs (inch pounds) in a criss-cross, star, or alternating sequence. Torque all bolts a second time clockwise or counter-clockwise around the pan to ensure none were missed.
• Fill the transmission with new ATF through the dipstick tube. The service refill capacity on the 47RE and 47RH transmissions is approximately 4 quarts, but this is only an estimate. Reinsert and check the fluid level frequently as you add fluid to prevent overfilling. When the dipstick indicates that the fluid level is within the normal range, start the engine and check the fluid level at idle; adjust accordingly.
• Cycle the shifter through all ranges (P, R, N, D, etc) and recheck the fluid level; add fluid as necessary. Finally, take the vehicle for a short drive and add fluid as necessary.