i changed the cv axles pass and driver side now my 4x4 wont engage is there a fill plugg on the 4x4 actuator housing for gear oil? all vacume lines look to be in good shape and no wires look bad either could this be a low gear oil issue sence i did loose some in the cv swap process i filled the diff with gear oil when i was done this is why i susspect the actuator housing has a seprate fill location maby the mechanical part of the vacume system located on the driver side axel tube of the front diff (dont know what its called) any sugguestions would be appreceated