Don't pay a mechanic. It is not a difficult job but you will take some time if you have never done it before.
There are six bolts holding the lower unit onto the midleg and one "Hidden bolt under the exhaust snout. So: under the transom clamps and swivel there is a connection for the shift linkage. Remove the cotter and pin. If the engine is tilted be certain the connector does not fall off the upper shift rod. Now remove the snout and all seven bolts. The lower unit will usually drop down so it is best to have someone hold it for you while you remove the last bolt.. There usually is a stainless collar and rubber bellows at the top of the drive shaft. Many times both will fall of while removing the lower unit. If they do fall off, find them .
The water pump is on top of the lower unit and held with four bolts.You remove those four bolts and slide the pump up the drive shaft. The impeller may or may not stay in the pump. In any case, remove the impeller and put in a new one.Don't lose the key in the shaft. Slide a new impeller down the shaft and over the key. Slide the pump body down the shaft. Lubricate the inside with a small amount of dish soap.
Looking down, rotate the drive shaft clockwise while pushing the pump body over the impeller and replace all four bolts.
Have someone help when you go to replace the lower unit. The splines will most likely not line up with the crankshaft splines and the water tube must be aligned with the water pump outlet. Turn either the crankshaft or propeller to try to align the splines.The lower unit is heavy so an extra pair of hands helps.
Someplace--might be boatdoc there is a generic video.
Depending upon the year Chrysler there are different size impellers so be certain you order the correct one.
