what is the "clunking" when i put into gear?

Changing the oil is basic on the Land Cruiser just use the correct oil. Did he feel the noise was transmission, transfer case, drive line or differential related? Make sure the correct oils are used, I 'm sure he checked for worn driveshaft U- Joints. There is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online These are not a very trouble some transmission.