New Trans odd Sound

[MRColler]

Here’s the rundown

I rebuilt an extra 46RH I had and installed it.. When I fired up the truck I heard a very fine ticking, almost like a louder then normal gear spinning but the trans worked just fine. I thought it might be the flexplate so i pulled the trans and since I was replacing it picked up a 2nd gen flexplate and installed it. But to my dismay when I fired the truck up again the fine ticking was still there.
I have no clue what it is.... does anyone have any ideas or things to check or test. Again the trans is working goood so I’m at a lose..

I Have a ticking sound that sounds like it might be the 6th cylinder.

 

[Crank]

Could be just a valve tap.

 

[MRColler]

I think I've figured it out. I believe its the piston lift pump.