I have a 2008 F250 XL with the 5.4L, ZF s650 transmission, manual transfer case, and 3.73 axles on 31" wheels. Here is my idea for an awesome transmission setup: Marry up a re-geared 3 speed to act as a granny low and overdrive. Has anyone heard of this type of mod being attempted? I have an attached chart which shows the torque curve over the 13 gear ratios. Yes, I know this sounds ludicrous for a 3/4 ton but I work in construction and will be pulling heavy loads on uneven terrain in high grade areas. Even if it takes me a minute to get moving through the granny gears at least I won't have to worry about burning out a clutch when trying to crawl or get a trailer moving. I got the idea for this from a video where a mechanic married up an old '85 twin stick transmission to his '90-something F150. I plan to work this truck pretty hard and would rather that strain be translated to the gearing not the engine. For those who might be tempted to ask why do all this on the 5.4L I am planning on an engine swap to the 6.2L in the 2015+ Super Duty and modifying it to run around 500+ Lb-ft of torque. With this gearing, and the low-RPM torque rating of that engine, this truck will easily pull anything I want it to, so long as it doesn't cost 30k to do it.