What year and chassis???
If its a 99 Ford F53, You may want to do a transmission filter change and flush.
You said heavy traffic, if this was very low speed, i.e. stop and go, and it was hot outside, you may have run some high temperatures on the transmission. The first couple years of the V10/4R100 didn't incorporate transmission cooling into the engine radiator, so under these conditions, its possible to over temp the transmission.
1999 Fleetwood Southwind 35S (Ford F53 6.8L V10 275hp 4R100 4 spd trans) - Toad 2003 Saturn Vue.
It won't do MACH 2, but I can get a sandwich and take a pee.