gonna attempt rear axle seals.. know pop rear cover to drain fluid.. but where do i fill it.. there is no plug in this diff... just a sensor in middle on the top... do i remove this to fill it? or am i SOL? 93 Ford Ranger 4X4 5 speed.

 

There is a fill plug on the front of the diff. beside where the drive shaft connects on the drivers side of the truck. It's a square hole just use a 3/8 extension on a ratchet and it will come out.

 

^ What he said!