Differences in PS pumps for XJ's

My 1996 XJ's PS pump is making noise. I have a 1990 unit from a parted out XJ. Both 4.0L auto's. It LOOKS the same. Are there any differences anyone knows of before I dive in and get myself stranded? (Its my only vehicle tomorrow.)

CW

Metric Saginaw was used all the way up - they should be the same internally.

As I recall, the difference between pax car Saginaw pumps was the mounting pattern (varies by vehicle model) and hose connections (varies less by model,) so if the hardware fits, it's at least a good temporary fix. You can do something more permanent later...

5-90

Make sure the pump has threaded mounts not through holes thats about the only problem you could run into