How difficult of a job is this to do? I have only replaced them on isuzu rodeos. Should I replace the timing chain while I'm at it? Info appreciated.

Medium difficult. Assuming 4.0 L six cyl. engine.

Disconnect the battery for saftey.

Basic auto mechanics. Nuts and bolts. Scaping the gasket and resealing. Removing the fan and belts as necessary. Heater pipe maybe tricky.

Refill with a 50/50 coolant mix.

I've done this a few times in a ZJ. It's pretty straightforward. It'll take about 3/4 of a Saturday.

You might as well replace the thermostat whilst you're at it. Two birds and all...

I got the new pump on, the seal was toast. New thermostat as well. Thanks.