Always check the transmission fluid at operating temperature with the engine idling in neutral.
Re-calibrate the Ergo-Control unit using diagnostic software.
You will likely need a ZF pressure gauge kit and specific pullers for the bearing carriers. Zf 4wg 150 Transmission Repair Manuall
The 4WG 150 utilizes multi-disc clutches. During repair, inspect the friction linings for discoloration or "glazing." If the steel plates show signs of warping or blueing from heat, the entire pack must be replaced.
If a major repair is required, a standard manual breaks the process into several key stages: Always check the transmission fluid at operating temperature
Regular upkeep is the first line of defense against transmission failure.
Inspect the charging pump and check for metal shavings in the filter. Electronic calibration error. The 4WG 150 utilizes multi-disc clutches
Transmission repair must be done in a "clean room" environment. A single speck of grit can ruin a hydraulic seal or clog a valve.
Never "hand-tighten" internal bolts. Follow the manual's specific Newton-meter (Nm) settings for the housing and valve body to prevent casing distortion. Where to Find the Official Manual