Fuel Guage Prob's

I recently had the fuel pump changed on my '88 cherokee by a local shop. Before the repair my fuel guage worked perfectly. After the work the guage moves all the way past the mounting screws on the side(3 o'clock position) of the guage when full. The guage only drops down to 1/4 tank and then I run out of fuel. NO low full warning light either. Now, I've heard that this is because something was bent or misaligned during the fuel pump replacement but I'm not sure what the exact repair is.... I've tried to report the problem to the shop but they try to tell me the guage is screwed. I need to figure out the problem before the shop will do anything. Please help....
Thanks Scott

I just went through this with my 90 Cherokee. We had changed the gauge first and then the fuel sending unit. The sending unit was defective
and when we replaced it again, it worked. The original OHM readings were way off. I checked with the FSU mfg and got the readings from
them and we rechecked it with a meter before we put the replacement in. The FSU was the problem. I would have them check that to see if it's the problem.
The OHM should read 0-4 at empty to 97-99 at full.