[dehaven]

99 SD 4wd auto, changed tran fluid, drained torque converter, refilled w/ 12 qts , went to restart, had HORRENDOUS metal sounding noise, sounds like starter staying engaged, but not likely? any ideas on what happened or what could be wrong?

 

[Fred svt]

It's most likely just the converter rattling.
Once the fluid is pumped into it, it should quiet down, providing it was quiet to begin with.
A rattling converter sounds much worse when you service them and their empty.

 

[JimTJr]

What FRED said!!! /ubbthreads/images/graemlins/shocked.gif VERY NASTY NOISE for sure,,,

 

[dehaven]

Appears you were correct! Threw in the towel and it didn't blow up... thank you for your quick response!