I replaced my rear abs sensor and it didnt get fully tightened. Had a little puddle plus some drips of rear differential fluid. Truck drives fine still. Should i add more fluid?? Help! Thanks!!

 

Just so you know, everyone who makes a thread wants a quick reply......to answer your question, of course you should make sure its full. Just like oil, transmission fluid, brake fluid or coolant. They have a capacity level and should be full for a reason.

 

Why was it installed not fully tightened? My suggestion would be to fully tighten the sensor so it doesn't leak, then top off the differential with the proper amount of fluid.

 

Correct just unscrew the fill plug, if it comes out you're good to go.

 

"A little bit of fluid makes a lot of mess."

 

I always used my pinky finger as a measuring tool: i'd remove the fill plug, stick my pinky finger in the hole, bend the tip down, and if there was oil on its tip of the finger, the level was good.
Depending on the amount of the puddle you saw on the ground, you should be alright, but it's better to be safe and remove the fill plug and check.