One final task before cold weather set in was to change the transmission filter and flush the tranny.
I'm glad I did this as I found a couple small problems.
The vent hose was plugged, making it impossible to add fluid to the transmission. Got that replaced.
Early model V10 / 4R100 do not have a tube-in-tube tranny cooler inside the radiator. I noticed this when I had the radiator removed while working on my exhaust studs. Mine does have an external tranny cooler radiator. This can be an issue at low speed when there is low airflow through the radiators. i.e. city driving in hot weather. I'll replace the OEM radiator next spring with one that has the transmission cooler.
The transmission pressure bypass tube/valve can get weak or fail. I was thinking about deleting it, but changed my mind and I'll put a rebuild kit in it next spring just to make sure its good..
Ford TSB called for a transmission inline filter on these early F53s. This filter has a history of leaks. Mine was leaking so I decided to replace it with a WIX spin-on.
When I flushed, the old fluid was a little brown but no unusual smell. I replaced the internal filter and flushed the tranny with 5 gallons of Valvoline ATF synthetic.
All this is documented on my web site.
F53 Transmission filter change and flush – 1999 Southwind 35S