Join Date: Apr 1999
Location: Midland County,TX, USA
Feedback Score: 0 reviews
Gross combined weight rating (GCWR) is the weight a combo of engine and drivetrain can get moving and then tow up a certain grade at a certain speed without overheating something.
So at that speed, up that hill, while grossing 18,000 pounds, the stock 460 can make it to the top without overheating or straining anything. The stock IDI non-turbo diesel has fewer horses, so it can't make it to the top of the pass with more than 17,000 pounds at that speed without overheating something.
As to stick shifter vs. automagic tranny, the key is getting the load moving. The automagic has a torque converter that almost doubles the torque coming from the engine at slow speed, so with the torque converter slipping and creating a volcano worth of wasted heat while doubling the torque available to the tranny, the load begins moving without "slipping the clutch". Yes, the torque converter is slipping, but it's designed to slip with no problem other than creating a bunch of heat that must be sucked out of the tranny fluid by a huge tranny cooler.
The stick shifter can tow the same weight after you get it moving, but you have to slip the clutch too much to get it moving. So the automagic has more GCWR.
That was then. Beginning with the SuperDuty pickups in '99 model year, Ford beefed up the stick shifters with a heavier-duty clutch and tranny, so the stick shifters had the same GCWR as the automagics.
My Sierra Blanca in the sig pic was a great pickup for 11.5 years. I sold it a coupla years ago. I drove a hand-me-down 2003 F-150 SuperCrew 4.6L 2V for a while, but it was unacceptable for towing more than a rowboat. Replacement is a 2012 F-150 EcoBoost SuperCrew Lariat that tows my 5,000-pound TT like a dream.