Have a clunk on the 2-1 downshift,everything else seems fine,just a pretty gook clank when slow rolling to a stop and she drops in 1st gear.
Auto tranny

 

This should be an easy fix and not a lot of money!

The noise or clunk you are feeling is most likely caused by lack of lubrication on the splines on the Yoke where it goes into the tranny.

Take it to a trans shop and have it lubed and this should stop the clunk.

I am getting ready to take mine in and have this done as my truck is starting to due this same thing.

I have 86+k and this will be the second time for lube on the splines.

good luck

jvp