Maybe you're on to something, Tim.

My 95 pickup with a shell has a 454, and gets 12.8 mpg L.A to AZ pulling a 4500 lb boat at 55-60 mph. Empty, at 65-70, it gets 12.8 mpg.

Good point, Tim. At various times, I had a '73 half-ton, and a '74 Suburban. The only thing that dropped mileage on the pickup, was a heavy 31' travel trailer that cost me about 1 mpg. Otherwise it was just like yours.

The Suburban had been warmed over by a speed shop sometime in it's past. It would pull stumps, or peel rubber if you wound it out in second and dumped into high. The standard evolution was one tank of gas, one quart of oil, or two quarts if I'd been running at 80. But I never saw a puff of smoke, or an oil drip. Slow, fast, empty, or loaded, though, fuel mileage never changed.

Your idea somehow connects with the "Dark Sucker Theory," and the effects of using double male extension cords. We should put ron to work on it.

Bill you can take this thread any where you want.What do you think about the deep alum tranny pans to help with its cooling. BRES

Most motor homes with the TH400 already have a deeper sump than autos. I believe the MH one has a depth of over 3 inches. I have not measured all aluminum pans, but the ones I have measured are no deeper.

However, aluminum is a better conductor of heat than steel, and fins make it better yet, so one of those pans would be effective. But I believe that the same amount of money would yield more cooling if spent on a good tranny cooler rather than a pan.

Just a note on trans coolers, which have been mentioned in 454-overheat thread. This is in the it-happened-to-me category. Couple motorhomes ago, I paid a licensed service garage to put on a trans cooler, which I thought wise for towing my restored, heavy, 24-ft Great Lakes-capable boat. First trip after the install, less than 2 hours on way to Lake Michigan, a fire started that consumed the Class B unit. Molten windows ran down the van doors, that hot. Fire chief guessed result of trans fluid leak that sprayed the exhaust pipe and ignited. Guess trans fluid is more flammable than motor oil, according to the fire chief. Just posting this as reminder to use extra care with trans cooler installs.
QUESTION for Mechanics: Can real pipe and fittings be used in lieu of rubber hoses and hose clamps that come in the trans cooler kits? Seems it would be safer. OR could trans cooler be routed so that potential leaks would not hit hot exhaust metal? Believe me, raging fires under your seat while driving make you want to eliminate potential causes in future.

The common scenario is that the tranny overheats and fluid comes out of the fill/dipstick tube, spills on the exhaust and ignites.

The best way to avoid this is to monitor your trans temp. Synthetic fluid is less liable to overheat, too, and has a higher flash point by 70 or 80 degrees F.

Another common failure is chafing. The lines and hoses really move around a lot under way. The hard lines are attached to the engine which rocks under torque, so there is a lot of opportunity for the hoses to rub. A free run is often not secure enough, so clamp it to be sure. Ty Raps get brittle with age and heat, so don't trust them. Sometimes I slit a short piece of old heater hose and slip it over a potential chafe point.

The common hose and clamp connection is very poor. The worm drive clamps are the worst. Ask me about my Jag V12. Lots of engine fires with those. The injector lines are hose clamp hell. VW had a similar problem with their early fuel injection. At best, the clamps should be double clamped with the screws 180 degrees apart and tightened once a year. They should not be tightened over 25 in lbs. And the hose should not be slipped over steel lines unless the ends are beaded or double flared. My preference is to bead the ends of the steel lines and use an Oetiker clamp. The 360 degree Oetiker clamps are the best. Spring ear clamps are good, too, as long as you select the right size so it maintains tightness as the hose shrinks. Hose should be replaced every few years, too. Only trans cooler hose should be used, not fuel line. I use Hayden #105. Hayden also sells a kit, #251 that includes the hose and some fittings.

The B&M 70266 and 70274 have 1/2 NPT female ports, so can be connected to steel braid or AN hoses. You could terminate the hard steel lines with fittings to accept the hose nipple.