wanting to change differential fluid never done it before does not look that hard. but the differential cover and bolts are extremly rusty and i don't see a drain plug so i have to take the cover out wich am a little scared that i f**k something up should i replace the cover and bolts and what type of lubricant do i use and how much. don't have the owners manual. also i know that i need a torque wrench what setting does it need to be for a 94 ranger. any help would be very helpful thanks
1994 ranger 4.0 automatic 18in wheels lowered sony xplod radio with i pod connector 03 ranger interior seats i belive everything else is pretty stock.