U.S. forces entered Afghanistan for radically different reasons than the Soviets, but the local reaction appears to be no different. Then, as now, the Afghani troops and the powers that be in Kabul were questionable, at best. More often than not, the troops were secretly sympathetic with the Mujahadeen, and fed them intelligence and support whenever Ivan wasn't looking too closely. The government was double-dealing, hopelessly corrupt, and utterly incompetent in trying to govern the whole of Afghanistan.
I don't see the mess our troops facing to be much different. They government will take our money, and the troops will smile and march with us, but at the end of the day, most of them would only be too happy to put a knife in our backs - figuratively and literally. I have zero doubt they would have leapt at the chance to set up one of our SEAL teams, if they had the opportunity.