GMC 12491886 Transmission Asm,Auto 4Msd (Goodwrench Remanufacture)

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To remove the transmission, start by disconnecting the negative battery cable and removing the engine cover and transmission fluid dipstick. On carbureted and TBI engines, remove the air cleaner assembly. Raise the vehicle, support it securely on jackstands, and drain the transmission fluid before reinstalling the pan. On 700-R4 and older 4L60 models, disconnect the TV cable and plug the hole. On 1995 and earlier models, disconnect the shift linkage, and on 1996 and later models, disconnect the shift cable. If equipped, disconnect the speedometer cable. Label and disconnect all electrical harness connectors from the transmission and remove the driveshaft and any exhaust components that may interfere with transmission removal. Remove the engine-to-transmission struts or transmission braces if present. Remove the converter housing lower cover to access the torque converter-to-drive plate bolts. Match-mark the driveplate to the torque converter and remove the torque converter bolts. Position a transmission jack under the transmission, unbolt the transmission mount, remove the crossmember and angular brackets, and lower the transmission to gain access to other components. Remove the transmission-to-engine bolts, dipstick tube, and disconnect the transmission cooler lines. If equipped, remove the transmission damper and support. Support the engine with a floor jack, remove the starter motor, and ensure all wires and cables are disconnected from the transmission. Separate the transmission from the engine while holding the torque converter back against the transmission. For installation, ensure the torque converter is seated correctly, raise the transmission into position and push it forward onto the locating pins. Install the drive plate-to-converter bolts, aligning the marks made during removal, and tighten them to specified torque. Install a new oil filler tube O-ring and then install the various components in reverse order. Adjust the shift linkage, throttle valve cable, or shift cable as needed. For 1996 and later models, use new spring clips to secure the cooler lines at the radiator, ensuring they are properly mated and secure. If the transmission has been drained, follow a specific fluid filling procedure to ensure the correct fluid level. Add approximately 5-1/2 quarts of transmission fluid through the filler tube, start the engine, move the shifter through each range, and check the fluid level with the shifter in Park while the engine is running. Add fluid gradually to bring it between the two marks on the dipstick, preventing overfilling.

Install a new oil filler tube O-ring and then install various components in reverse order. Adjust the shift linkage, throttle valve cable, or shift cable as needed. For 1996 and later models, use new spring clips to secure cooler lines at the radiator.