Hi,

I have a '99 F350 V10 gas dually that I use primarily for towing my
5th wheel camper.  I bought the truck 2 years ago and have put about
3000 miles on it.  The odometer reads about 51,500 miles.

As part of routine maintenance, I want to replace the transmission fluid.

The Ford dealer says they can do a "power flush" for $139.  I am guessing
that this means opening one of the fluid lines and applying new fluid in
one end and emptying old fluid out of the other.  Bearing in mind that I
use the truck for mostly towing the camper, is the "power flush"  
sufficient, and does a transmission cooler have any impact on this, as I
believe (haven't looked yet) that there is a cooler near the radiator.
What about the filter assembly that is located in the transmission pan?  
Should I also have it changed by the dealer?  If so, the power flush would
not be an option since the pan would have to be dropped to get to the
filter.

Or, should I do the work myself? I noticed that my transmission has a drain
plug in the center of it even though my Chilton book makes no mention of
the drain plug.  After removing the fluid I could replace the filter
assembly also.  The Chilton book says that the gasket is reusable.  The
drain plug would make this much easier than dropping a pan full of fluid.

If I have a transmission cooler, is there a filter for it that should be
replaced?  Do the cooler lines need to be blown out?

Thanks for your thoughts,

Jack