C4 Cruise-O-Matic/Select-Shift transmission band adjustment information in your January 2011 Mustang Monthly requires clarification.
Your Ford Shop Manual is always the best place to find factory specifications and recommended adjustments. And for the most part, it's a good idea to follow factory specifications whenever you're working on your Mustang.
There are always exceptions to every rule including factory specifications. Engine builders, for example, don't always follow factory specifications especially if they're building racing engines. Clearances are normally set looser due to the extremes of racing (heat).
Think of factory specifications as a happy median - an average - of what your adjustment should be. For example, if you still have a point-triggered distributor and your Ford Shop Manual calls for an .017-inch point gap, you might want to go wider to .020-inch allow for rubbing block wear. As the rubbing block wears, the .017-inch gap will find itself quickly even with ignition grease.
Valve adjustment can be thought of the same way - either looser or tighter depending on what you want the engine to do. Same applies to piston ring end gaps, piston-to-cylinder wall clearances, connecting rod side clearances, crankshaft endplay, and more. It really is up to the builder to determine proper adjustments based on what has worked for them in the past.
In our C4 service article in your January 2011 Mustang Monthly, we specified 10-12 ft/lbs of torque and backing off 1 to 1 1/2 turns for intermediate band adjustment and 10-12 ft/lbs and backing off 2 turns for low-reverse band. This is in direct conflict with Ford Shop Manuals of the period, which recommend 10 ft/lbs and 1 3/4 turns for intermediate band and 10 ft/lbs and 3 full turns for the low-reverse band. Automatic transmission band adjustment should always yield to factory specifications as a baseline adjustment. However, automatic transmission shops worldwide have band adjustments that work well for them. Not all of them follow the Shop Manual. In fact, very few follow Ford's factory specifications because friction materials have change a lot since these Shop Manuals were published 45 years ago.
It is a good idea to consult companies like B&M, TCI, and California Performance Transmissions (Art Carr) and get their respective opinions on proper band adjustment before tackling your C4, C6, or FMX. We work closely with three shops in Southern California - Mike's Transmissions in Lancaster, TRC in Chatsworth, and Mustangs Etc. in Van Nuys. Our instructions in the C4 service article were based on what we've seen time and time again working with these shops on C4 transmissions.
When you are performing band adjustment on your C4, C6, or FMX, you are adjusting band clearance and tension around the drum inside. Think of your transmission's bands as drum brakes, which stop drum rotation at specific times in transmission operation depending on what gear you're in. We want bands to grab - not slip - when the servo is applied. This is why you cannot always trust Ford Shop Manual instructions. No two band assemblies are exactly alike. Aftermarket and original equipment bands and friction materials are not the same. This explains why our specifications don't always match the Shop Manual's.
It is important to remember the importance of consulting your Ford Shop Manual for factory specifications. However, always keep in mind a lot has changed since these manuals were published. Use your best judgment or consult with a professional whenever you're in doubt.