Engine runs, but vehicle does not move in any gear
Check the ATF level, and check the ATF cooler lines for leakage and loose connections. If necessary, clean the ATF cooler lines.
Check for a loose shift cable at the shift lever and the transmission control lever.
Check the stall speed.
Check the line pressure.
Improper alignment of ATF pump and torque converter housing may cause the ATF pump to seize. The symptoms are mostly an rpm-related ticking noise or a high pitched squeak.
Be careful not to damage the torque converter housing when replacing the main ball bearing. You may also damage the ATF pump when you torque down the main valve body. This will cause the ATF pump seize.
Install the main seal flush with the torque converter housing when replacing the main seal. If you push it into the torque converter housing until it bottoms out, it will block the fluid return passage and result in damage.
Check the regulator valve in the regulator valve body for free movement, and check the valve spring for wear and damage.
Check the ATF strainer for debris. If the strainer is clogged, find the damaged components that caused the debris. If no cause for contamination is found, replace the torque converter.
Inspect the differential pinion gears for wear. If the differential pinion gears are worn, replace the differential assembly, replace the ATF strainer, thoroughly clean the transmission, and clean the ATF cooler and cooler lines.
Replace the torque converter.
Inspect the countershaft and secondary shaft for wear and damage.
Check for a misinstalled transmission.
Low ATF level
Shift cable broken or out of adjustment
Connection between shift cable and transmission or body is worn
ATF pump worn or binding
Regulator valve stuck or spring worn
ATF strainer clogged
Mainshaft worn or damaged
Final gears worn or damaged
Transmission-to-engine assembly error