Sorry i have to ask again, i didnt get any reliable answers?

Lol it's so cute an ARMY guy TRIED to answer you about a Marine question, but I can do you one better. I am a Marine and I happen to be a 3531, (3533's got disbanded and are now all primarily 31's with a secondary MOS of 33.) But anyway, I have been in Motor T for 7 years. In those 7 years I have gone to combat, and assisted the infantry like you said. However, in the war of today, the fight is wherever you happen to be when outside the wire. So just know if you go into Motor T you could find yourself in a firefight or ambush. So, moving on, in the rear your duties will include washing, fueling, loading and off loading personnel, gear, equipment, ammunition and supplies. In war you could be doing the same thing or you could volunteer to get other licenses. I.E. an ambulance license. I got one as a PFC and worked with the Navy Corpsmen in Iraq. Whenever someone was hurt or needed medical aid, I took the corpsman and the ambulance out to the site, and broguht the wounded back to the hospital. As an ambulance driver I also got to go to EMP school, just in case the DOC goes down. You could also volunteer to get a TT (tractor trailer) license (long haul gear and DRMO) , Emergency Vehicle license (become a roadmaster, I did that as a Sergeant), a bus license (drive school buses on base or work at a school house, I did that as a Lance Corporal) As an operator you will also be responsible for 1st and 2nd echelon maintence on the tacticle vehicles, all diesel. Hopefully I was able to help, good luck with your decision. :)