Prop to High RPM on downwind

I can't find it right now, but Lycoming had a publication in which they
advised against going to low prop pitch for deceleration of the airplane.
They said it caused detuning of the dynamic counterweights on the crankshaft
("harmonic balancers"?) and was the demonstrated cause of damage to certain
of their engine models. Although my engine was not listed in the affected
models, it seems that the same principle applies, and I have avoided going
to the high RPM setting until power is reduced on final, for engine
protection as well as noise. Supplement your printed checklist with GUMP
checks, including one on short final ALWAYS.

Stan

"Mitty" wrote in message
...
I've been taught to set the prop to high RPM on final, but I don't like
this very much because then, when I run my checklist for the first time on
downwind, I have to leave one item "open."

So what's wrong with doing it on downwind? (This in a Cherokee 6 or and
Arrow) It seems to work fine, does not disarrange the engine, etc. I
suppose there is some small noise increase, but hardly much.

So (1) is everyone taught to do it on final? (2) Why? (3) What's wrong
with doing it on downwind?

TIA