2000 Ford F150 tranny troubles

I have a 2000 Ford F150 7700 lb payload 4 x 4 truck. It has about 50,000 miles on it most of which is light highway use. I occasionally tow race cars etc with it. I don't plow snow with it. Recently the transmission has repeatedly held in 1st gear way way tool long when I first start to drive it. Now recently it has taken about 4 miles of driving before the converter locks up. After the truck is driven further and gets warmer it acts normal. I have heard that these trannys are quirky. I have also heard that Ford dealers have a fluid flush system where they flush out all the old ATF fluid, including what is in the converter, and pump in new fluid. I am told it is night and day after it is done. I think the dealers get over $100 for the flush. My tranny is definitely acting abnormal. I bought a filter and the Mercon V fluid to do a fluid & filter change, but I doubt I will be able to drain the converter. I think it holds something like 16 quarts and Mercon V aint cheap! Any thoughts welcome. Thanks, Peter. [img]/phpBB/images/smiles/icon_confused.gif[/img]

I have seen problems like this in the past, one of the fixes was the TPS was bad. This makes sense because your electronic trans is not recieveing a signal from the TPS to to tell it how much throttle is being used. But since your trany acts normal once warmed up I would defenently start with a full tranny flush and yes it does work like magic we do it all the time at my dealer in florida.. If this does not correct your problem then you would have to look in to it deeper. Example tranny bands, blocked filter internal gear damage............ My personal belife is it is fluid related!!!!!!