Hi all, I posted about a year ago regarding my '99 B3500 5.9 transmission not wanting to shift into 3rd or reverse after a fluid change and "parts cannon" application. Well, I return with an update. I replaced the transmission with a used unit from FB marketplace that was *supposedly* rebuilt not too long ago. Even has a sticker on the bell housing that says "Rebuilt in the USA!!" I'm not sure how much I believe it, but maybe I'm just jaded from past marketplace transactions. Regardless, I got the transmission in with a new torque converter, swapped over whatever sensors I needed to, flushed the trans cooler, and put fluid in it. Immediately after starting up, I got a strange whining noise. I'm concerned it's either the pump or torque converter. I prefilled the TC and quadruple checked my fluid level, went for a short test drive then topped off the fluid again, and the sound has not changed. It drives and shifts just fine, going through all gears no problem.
It sounds a lot louder on camera than it really is, but that's probably good for sharing purposes. As you can tell, it changes with engine speed. Any thoughts? Really don't want to pull this big SOB out again, but I'm guessing I'm out of luck.

 

Is the starter not disengaging from the flywheel???

 

I considered that, but put my stethoscope on the starter and the whine didn't get any louder. I'll pull the starter this afternoon and see what happens.

 

Sounds to me like a bolt is rubbing on the cover on the front of the transmission.

 

This was the correct answer! A boss on the flexplate was coming into contact with the sheet metal lower cover on the front of the transmission. Some persuasion with the ole Tonya Harding got it worked out and we're back on the road. Thanks to both of you for the suggestions!