5r55s whining noise

[Someguywithatrans]

I have a 2008 ford explorer. Front cooler got clogged. I got a new case with the bore already reamed and sleeved. Used a 2005 ford mustang for parts. I used every single part except the torque converter. I used another torque converter i had for a 2007 explorer. Installed the transmission. Drove fine but there was a winning noise every morning or if its sit for a few hours. So does a whining noise when its cold. Guy brought it back because if the noise. I tore it down again. Replaced the pump and torque converter with other parts i believe to be good from a 2005 ford explorer. Oh and i installed a external cooler the 2nd time. Both times it makes a noise. Drives fine Though. I did however use dex/merc fluid both times. Then realising it takes mercon 5 i changed the fluid (as much as i can with just dropping the pan) and filled with mercon 5 and some additive to make dex/merc fluid preform as a merc 5. Does anyone have any other idea what it could be besides the pump, torque converter, or fluid. Looking for other ideas as to what it could be? Maybe the fluid inside the trans is still to thick. Any help would be greatly appreciated

 

[974X4BLACKSPORT]

Put a gauge on the hyd. test port and see what the pressure is doing when it is making the noise.

 

[JK080]

If you end up having to pull the transmission again you may want to install a empty case just to support the starter to start the engine. If the noise is still there then its not a transmission problem.

Make sure the dowel pins are there too.

 

[Someguywithatrans]

Put a gauge on the hyd. test port and see what the pressure is doing when it is making the noise.

Im getting the car back on saturday. I figure out how to do that and ill give an uodate on my findings. And i have to take the trans down again ill install an empty care just for the the hell of it to see if it is the trans. I have a strong suspicion that it is the transmission but ill see. Thank you both for sharing your suggestions. I appreciate it.