Rebuilt th400 whining noise

[Jebadiah]

Hey all, so I tried my hand at rebuilding my th400. Rebuild went quite well I thought, with the help of the workbench how to series book. Got it all back together and in the truck. It shifts great! Problem I noticed though. It has a whine. I can tell it is not a hard part, it sounds like hydraulics. When starting the truck cold it has this whine all the time and continues until the Trans is at operating temp. Then it only whines in 1st and 2nd above 2k rpm. On top of that you can hear the planetary whine like it normally did before, so i can rule that out. What could cause this? Fluid level is perfect on the line. I hauled a trailer with the new transmission for the first time last week and it worked exceptionally well. Should I even worry about it?

 

[Schurkey]

Faulty pump including worn "gears" and a stuck pressure-relief valve

Faulty torque converter

AIR LEAK INTO THE PUMP PICK-UP. I always install DOUBLE O-rings on the pickup tube that shoves into the pump and connects to the filter. Similarly, I install double O-rings on the modulator, too. Tired of "pan gasket" leaks that turn out to be a seeping modulator.

Faulty/plugged filter

Mis-calibrated dipstick

 

[Jebadiah]

Faulty pump including worn "gears" and a stuck pressure-relief valve

Faulty torque converter

AIR LEAK INTO THE PUMP PICK-UP. I always install DOUBLE O-rings on the pickup tube that shoves into the pump and connects to the filter. Similarly, I install double O-rings on the modulator, too. Tired of "pan gasket" leaks that turn out to be a seeping modulator.

Faulty/plugged filter

Mis-calibrated dipstick

Gears looked ok when I rebuilt the pump. I will try changing fluid, higher quality filter, and double o ring. I almost thought it sounded like there was air cavitation going on like in tractor hydraulic pumps.