I have always had great luck with Craftsman floor jacks, have a 3.5 ton beast that I usually use. I also have a 2 ton AC hydraulics low profile jack that I use on cars too low for the beast.
Even though it was a present, any chance you can return or exchange it?
if the jack doesnt work...get a new one...its not worth it to try and fix it if it may fall on you while ur under the car....i think itd be a good investment to just go out and buy yourself a new one...thats reputable...like a craftsman...just my $0.02
I have had two jacks die on me before. Once was very scary, I was under the car, changing out the x pipe and it gave out and just started dropping. I wasnt using any jack stands at the time (i know i know BAD IDEA). Well, I have a craftsman jack now and I have 2 sets of jack stands...can never be too safe.