88 mj with electrical troubles

Ok so I hooked up the plow and went to work this morning. Used the plow a couple times and then my volt meter dropped to approx 10 volts. It didn't drop slowly...I saw it take a nose dive b/c i just happened to be looking at the dash at the time. Is it possible for an alternator to take a dump that fast? or do they drop off more slowly?

It could and so could your battery.

The mounting of the alternator can cause stuff to get jammed into it.

Could have been snow getting packed into it. I would check all the grounds out. All the banging around during plowing, could have jarred something loose.

The alternator may be marginal, and may have been that way for a long time. It may have enough moxie to keep the engine running and even run the lights, but the pump motor for a snow plow uses a LOT of juice. Both my brother and I used to plow with '78 full-size Cherokees with heavy-duty alternators and huge batteries, and when working a tight driveway where the pump was used often, the alternator and battery couldn't keep up.

Take your alternator to an Auto Zone or Advance Auto and have it bench checked.

Hey guys, thanks for the quick responses. Based on the advice I get here the MJ and my XJ are still running. Popped off the pos. cable while the truck was running and the motor died...guy at the local parts store told me to try this one. Replaced the alternator. Just for giggles (and some sound advice I got here) I yanked the battery and had it tested. Guess what...on its last legs. So I sprung for the 105 amp alternator (the my originally had a 61) and an Optima Yellow Top. Any of you guys running a dual battery set-up? Space is kinda limited sop any advice on how you did it would be appreciated.