2011 chevy.... Problem found

[PUREBAY2200]

I bought my truck in October..... In November I started hearing a high pitch rattling from under the truck.... Took it to 3 diff chevy dealers..... No help..
So I just stopped trying to figure it out.
Went in today to get an oil change at the local fast lube. Guy finished up and asks me how I like the truck. Told him bout noise and he started Lookin at all the areas he thought could rattle. No luck. Last thing they do is check the transmission fluid....... Pulls dip stick out...... Transmission tube casing comes out with dip stick..... Damn thing has been broke from the main hose since NOV..... Proof the chevy dealer didn't check the tranny fluid. And has no trouble shooting skills what so ever!!!
So I take it to the chevy dealer, throw it on the service manager desk and tell him " heres the damn problem!! Let use that warranty and fix it!!"
They can't figure out what part I need. Chevy uses 3 diff tranny tubes , depends on what plant it came from. Thankfully they had the correct one in stock.
Gettin it fixed in the morning.