I have a 2005 Dodge Ram pick up with 5.7 engine and auto trans. I have a tapping sound coming out of the trans. It gets really loud right before it down shifts. From a stop it is slight.

 

How many miles? Hows the fluid level and condition? Transmission ever been serviced?

 

220,000 miles fluid is full and is not burnt never been serviced

 

If it's something internal it may be time for a service. Really can't tell you definitively over the Internet.

 

Possible Cracked flex plate. Or broken torque converter neck

 

Either way, best to get it properly diagnosed asap before more damage is done.

 

I'd make sure a u-joint isn't ready to go. Get under the truck (use proper safety precautions) grab the drive shaft & check for play. Also inspect the differential yoke.

my 97 Ram would make that noise when the transfer case chain had slop in it. Noise went away with new transfer case.