Synthetic transmission fluid ?

[Ice Cat ^. .^ ~]

Hope everyone is having a great weekend.

My husband just finished looking at the catalytic converter and it
looks like new!
My relief of replacing that has turned to worry about the transmission.
That is about the only thing left I can thing of to cause this
*strange whine, growl, howl* when there is load on the car.   The
sound is rpm dependent and does *not* happen when the car is sitting
still idling.  The sound changes when I take my foot of the gas, but
is worse when the car is cold than warm which is giving me
new-transmission heebie geebies.   :-(

He is ready to change the transmission fluid to synthetic (as
suggested by a great member of our list whose email I have lost track
of . . . temporarily).

I am wondering if there is a brand or a place on a Saturday that
someone might recommend ?

Thanks.    Cheers,   Fay

             Create a great day !

                                                                       ^. .^  ~