I asked this in another forum, will try here also.
94 F250, 460, E4OD.
Recent installed the rebuilt motor. Now sometimes get a fast rattle sound, and a whirring sound, then it goes away for a bit, then whirring sound comes back. Rattle only seems to be on acceleration. Only does it when driving, not when parked in idle. Wondering if i put the flex plate in backwards? Or any other ideas?
​​​​​Motor was completely rebuilt, new bearings, pistons, rings, cam etc.
Thanks

 

Confirmed flexplate is installed correctly with weight and lip ring facing the motor. Issue is a rattling sound on acceleration, and a whirring noise that comes and goes. Does not do it in park at idle. Tried power braking and does it a little bit. Over 1500, it seems to go away. Transmission was supported during removal and install. Torque converter never shifted, and motor to transmission slid together smoothly.
I am at a loss here. Truck runs fine even when making noise, and no problems on gauges. Help. Help.
Thanks

 

Did you check the tranny and power steering fluids level?

 

Flexplate might be cracked.