Jeep Repair: leak, jeep cherokee country, oil pressure sending unit

Question
I just brought a 1996 jeep Cherokee country I went to get a oil change in they would not change it because they said it was a bad leak. I took it back to the person i brought it from and they said it was a something with the transmission holes in needed a clip or something but I thin when i start the jeep i here knocking in the motor what could this be

Answer
A lot of these jeeps have a slight knocking noise, the motor is just wearing out.  For the most part a jeep will run for a long time if the knock is slight.  As far as the oil leak goes I would have to take a look at it.  The most common leaks are the rear main seal, oil pan gaskets, valve cover gaskets, possibly the oil filter relocator, could also be the oil pressure sending unit right above the oil filter on the right side of the engine block. I am unsure of the clip they are talking about.  Hope you found this helpful!