I have an 05' 3500 CRD with 55k miles on it. A tree fell on it and crushed the hood, but not a total pancake. Got a new windshield and was able to drive it to the body shop. The body shop is a reputable place that is highly recommended by my insurance agency.
No real damage to any internal components or engine bay. Got my truck back from the shop let it sit for a couple of days. Drove around and when starting it i noticed it started a little slow, this happened several times that day as I went to stores. Eventually the check gauges light came on, the alternator gauge was bottomed out.
I let it sit for a day checked it this morn and it started very slowly, watched the alternator gauge. it was very low for about 30 seconds then it hit bottom and CG light came on.
Passenger battery has what looks like possibly acid on the top of it. From a quick look there appears to be no damage I complained to the shop, saying, Hey it worked going in and it came out and it does not. They obviously don't want to buy an alternator though.

Any ideas of what I should check to make sure it is not something besides the alternator. Or if the alternator should be changed.

PLEASE HELP.

 

auto zone or kragen do free alternator checks in the vehicle or put a volt meter on the battery post and see if it charging the batteries, anything over 13vdc means the alternator is working

 

check the drivers side battery... there should be a cable running from the passenger battery to the drivers battery, connects on the postive terminal i believe. double check that, maybe they disconnected it. but thats what it sounds like cause my passenger battery was getting hot and spewing stuff and i double checked my connections and found the cable coming from the passenger to the driver wasnt connected. fired right up once i connected it.