I'll toss in a comment here Steve, re the transmission.
I have met two F250/BT owners who have had a transmission failure.
Both parties tow large heavy units over 21', fully optioned and most probably VERY heavy.
Both of these owners were using a converter lock when the transmissions failed.
You will find that when the F250 is loaded up and towing a heavy trailer that you will get some transmission slip, (really converter slip), when the auto changes up a gear when a heavy foot is applied to the little pedal on the right.
This is more evident when starting on an uphill climb. (Unlike rice burners the Effie will actually change UP a gear on hills with all the power available.)
It will also occur when changing down a gear.
The effect is that the engine will rev past the required point, by between 200-300 revs, and then "slip" back to the required revs. Sometimes it is necessary to lift the right foot a little to stop the slip.
The slip is designed to soften the load on the transmission. Without it the impact on the tranny components could go beyond the design limits.
A little like what a driver does with a clutch when operating a manual. You let the clutch out as required by the load, hill, gear selected etc.
If you drop the clutch on a powerful vehicle you can break an axle, tranny output shaft or some other component.
Some owners do not like the slip affect and take steps to eliminate it.
To explain, the transmission oil pressure that controls the amount of slip in the converter is controlled by computer operated valves.
The computer that controls the valves tells them when to open, how far to open etc.
The computer assesses the load on the tranny and opens the valves appropriate to the conditions.
There are electronic overrides available that override the computer commands to these valves.
They are normally used for competition, not for towing.
The tranny is really snappy when using these devices, feels great, whacks between gear changes like a Ferrari.
Then it falls to bits.
Most of the aftermarket engine tuners like the Superchips have three power programs available.
The first is for heavy towing, gives more power, better economy, does not alter converter valve controls.
Second program gives more power again, modifies converter valve settings and you can only tow light trailers and not load up the truck.
Third program gives a frightening power upgrade, almost locks converter and you should only use it with a lightly loaded vehicle and definitely NO TRAILER.
An F250 7.3 with the 3rd stage of tune will smoke the tyres to the rims if that is what you want.
This is a rather simplistic explanation, not too technical but one that I hope most can understand.
Regards
Bob
