Tow/Haul Operation on the 48RE
The 48RE also includes a “Tow-Haul” button on the shift lever. This feature locks out overdrive and locks the torque converter clutch. If you engage Tow-Haul at speeds above 50 mph, the transmission will shift or stay in third gear and the converter will lock. If you shift the transmission manually to second gear when you slow down to below 50 mph, the transmission will shift down to second gear with locked torque converter.
The safe input limit is 567 Lb/ft. By safe it means the limit that will make the trans last at least through the extended warranty period, and most likely as long as an owner could reasonably assume one would last under normal conditions (ie 100,000 to 120,000 miles)
Many exceed this amount, and the trans still holds up, but the bottom line is the more power through it results in more heat and stress, and reduced life.
The 600 is torque managed to a max of 567. The 33 lb/ft loss is to account for accessory loads, A/C, fan, and generator. If the accessory loads are high, the engine is making 600 less the load. no loads, it is managed to the 567 max.
The 555 is able to run full tilt, the 600 is torque managed. That being said, all 2003+ torque manage during shifts to save the trans.
