Squeaky noise in engine compartment only in drive
 

From time to time I hear a squeaky noise when it's in drive. Like I have to turn the engine off in the drive thru just so I can give my food order. I can't tell where it's coming from because of the Cummins normal sound. I took a video of it (really for the sounds). I can post it tomorrow if need be. On the engine I've only ever replaced the belt and water pump and a/c. I'm thinking it might either be the starter or alternator. On the 13th I'm towing a 7,000 lbs. travel trailer (dry weight) to Ft. Benning Georgia from Lubbock, Tx. I don't want something to fail on the way so I'm trying to get info to maybe change the part now or not.

U can rule out the things U mentioned, does it do it in park. seems as the TC or maybe the fly wheel plate may be cracked, If it only does it in drive thr engine is probably out of the Question, does it do it in reverse, drive 2 drive 1, "it may be called the flex plate" Btw fill in the info on U'r truck so we know what we are trying to solve