Het brother yes this is very common, just replaced one yesterday on the passenger side. Yes the service manual says to remove the dash but it is not necessary. I actually have a set of long needle nose pliers that are 16 inches long and it makes the job a joy to do. If you remove the glove box it will give you a little room to work from there as well. I just take the whole plug out of firewall and put sealant on the plug itself and carefully feed it back through and snap it into place. There is no grommet at all, the drain plug has a thin black seal on it and I apply the sealant to that seal on both sides.