Again, it is a good idea to begin the transmission removal procedure by referencing the OEM service literature. We have outlined here a general procedure that applies to a typical truck chassis but remember that each chassis is distinct. Pulling a transmission can be quick and easy in some COE chassis and long and complex in chassis such as garbage packers.
1. Remove the chassis battery ground cable.
2. Drain the lubricant from the transmission.
3. Remove the shift lever from the transmission. Remove the shift tower from the transmission and cover the tower flange with a rag.
4. Scribe a mark on the transmission output yoke, the drive shaft flange, and the output shaft stub on the transmission. Aligning the scribe marks on reinstallation will ensure that these components are correctly installed.
5. Separate the U-joint at the transmission and remove the drive shaft.
6. Disconnect any electrical connections from the transmission.
7. Disconnect all chassis-to-transmission air lines.
8. Remove the clutch lever return spring, then mark and disconnect the clutch linkage.
9. If a hydraulic clutch is used, disconnect the slave cylinder assembly and use mechanics wire to support it on the frame or cross-member. It should not be necessary to separate any hydraulic lines.
10. Support the transmission with either an overhead hoist or, from below, a transmission jack. The transmission should be securely supported.
11. Remove the fasteners that attach the transmission to any transverse frame brackets. Next take a look at the engine/transmission mounts. If the engine mounts are located on the engine flywheel housing, simply remove them. Some OEMs, however, place engine mounts on the transmission bell housing. If this is the case, you will have to support the full weight of the engine securely before uncoupling the bell housing.
12. Remove the bell housing to flywheel housing bolts. Gently separate the transmission bell housing from the flywheel housing by pulling rearward. Try to pull the transmission away from the engine while maintaining alignment.
13. Remove the transmission from the vehicle. You may have to use a frame scissor jack or a frame supported chain hoist to raise the truck chassis high enough to get the transmission out from under the frame. Never place any part of your body under any component supported on a hydraulic jack or chain hoist.
14. Use a cherry picker to raise the transmission from the transmission jack and mount it on a transmission overhaul fixture.