If it's any consolation we had the same issue today with an inner on the drivers side. We got it seated, we thought. Went for a little test drive and the boot tore and left a heck of a mess. Gonna order a new axle and replace the complete assembly.
I'm not trying to alarm you, but according to the owners manual the cooling system capacity is 11.6 quarts. If you had to add 2 gallons it only had 1/3 of the coolant in it. I'd recommend you drain it and replace with a 50/50 mixture of the correct fluid. I'd also suggest you inform the...