New alternator and still not charging/ working

The other day my volts dropped off and my alternator sounded like a supercharger. removed it found a hole in it. Replaced and then ran the engine after charging the battery. Volts still in the red. Brought alternator back to Kragen, they tested it twce and said it was fine. Go back home reinstall on rig and take for a drive. After drving for a while volts drop off the guage and my rig craps out. No juice. Tested back of the alternator with engine running no juice. Any ideas? Its a 89' MJ with the 4.0

its a shitty allternator and it stops working after being under load for a bit, stops working drains the battery and rig dies.

take it back say you dont car how it tested and try another one if still doing this maybe try another brand.

all this assuming you have it all properly hooked up. no missing wires ect.

If the little yellow wire going to the back of the alternator has no battery voltage with the key on, the regulator (alternator) won't work. The yellow wire is a voltage feedback to the regulator and also acts like a switch to open (turn off) the charging circuit when the key is off.
If the fusible link on the big red wire is toast, it probably won't charge the battery. Fusible links can be an iffy thing, they kind of turn to burnt slag inside and can be a sometimes thing. Though they usually burn cleanly through.
If your radiator has a pin hole leak that is squirting on the alternator, this can burn them up fast. An alternator can stand some water, coolant seems to kill them quick.
Clean all your major connections, battery plus,battery ground, red wire from the alternator to the starter relay. make sure they are shiny clean and the bolts are tight.

it was the fusible link for the constant 12 volt supply. Thanks for the help.