Ram tranny problems

Well the abs scan said the rear abs sensor fault. One problem narrowed down. As for the tranny I talked to a guy who all he does is mopar trannys at a local dealership said that a lot of plow trucks get these symtoms. I guess if you go low to reverse repeatedly that its a common problem. He said pull the pan and look for a 2 inch flat piece of metal on the bottom of the pan or on top of the vavle body. He said this piece of metal holds the low/reverse band in place and sometimes falls out when used hard. No light will come on and reverse will work most of the time. He said he thinks you can spin the band and put it back in without a full tear down. I've never had one apart does this make any senseto anyone else?