Check the battery cables at both ends for no corrosion and a tight fit.Next attach a voltmeter across the battery posts,voltage should be 12.6volts for a fully charged battery.If its lower than this,you'll have to remove it and get it tested and charged at Autozone or leave it attached if the car is driveable,because they can test it while its in the car.If the battery is good,test the alternater.Disconnect the neg battery,attach a test light to neg battery terminal and neg battery post,is test light on?If yes,disconnect the alternater wiring harness,did the light go out?If yes,the alternater is defective or there's a short in its wiring harness.If light didn't go out,you've got a short somewhere else.Start pulling fuses til you see the test light go out.When light goes out that's the circuit with the short.Once you locate this circuit,reinsert the fuse so the light comes back on.Now start disconnecting wiring harnesses,switches,etc in that circuit til the light goes out again

Did you wire brush or scrape the connectors when you replaced the battery? Even if there's no corrosion the connectors may have a buildup on them that will create a high resistance and cause slow cranking. Try removing the cables and wire brushing the connectors. While you're at it inspect the other ends of the cables for clean, rust free connections.

after you verify you have a hot battery with good connections the next problem will be the starter

You probably didn't tighten the battery terminals properly

Could be a bad ground. Most probably a bad starter.

It could be the starter or the alternator.

your alternator is dead and you ran on straight battery voltage

knfakm

Just bought the truck a week ago, and its always cranked over very slowly. Today I parked it at a gas station came out and it turned over very slow and wouldnt start, I swapped out the battery and it fired right up. I drove it home and now its not starting again, not clicking, no sound whatsoever. Im thinking possibly a bad ground somewhere? Any input is much appreciated.