[muddog321]

Changing the filter has no effect on the PCM/ECM. Never said if 2wd or 4wd but the 4wd uses a deeper stepped pan thus a longer filter. Did you pull the dip stick at operating temp when running and check the level? If this happened right after the filter was changed could be that or he disconnected/cut some wires to the many solenoids in the trans internally or externally. Or as things sometimes go another sensor started failing right after that which was not related. How many miles? Any codes or SES light?