blt2ski wrote:
"Hannibal" was towing a 12K 5w with a Dodge 5.7 and 3.73 gears. He changed out to 4.56 gears later. I am recalling at the end of the day, he liked the 3.73 better overall. But get up and go was better with the 4.56. You might try and PM Steve to get some better comments on how it did.
i've pulled a couple of time a 12K equipment trailer with my 255/330 GM vortec 5.7. 4.10 gears and a 4l80E which has horrible trans gearing from a towing standpoint. I could hold 45-50 on a 2-3% grade in 2nd gear at 4000 without issues. I am sure more hp would be faster per say. I would not have and issue pulling this trailer with a 6.0 and the 6sp auto from GM. Be it rated for it or not. It would do it fine.
Also, depending upon the motor in the Ex, a newer gas rig may have better performance than an older 250-275HP 7.3 psd.
Marty
It was a 12,400 lb GVWR 5th wheel. Actual weight was 10,040 on one empty tanks trip. It's probably been close to 12k lb though. The 5.7L Hemi powered 2500 did fine with the 3.73 ratio. At 65mph in O/D, it ran 2000~rpm. Slight inclines or headwinds put it in direct at 2700rpm. On the uphills, yes we have some in north Florida, it ran 4200rpm (peak torque rpm) in 2nd at 60mph with some power to spare. When I had to have the rear end rebuilt at 97k miles, I went with a 4.56 ratio. It made the rig feel lighter. At 60-65mph towing speeds, O/D was closer to where direct drive was with the 3.73 at 2400rpm. Direct was 3300rpm. Problem is it still needed 2nd for the steeper uphills but 2nd was out of reach. So for us, the 3.73 was a perfect match for the rpm of the 5.7L Hemi towing highway speeds. The 3.73 also worked out better for us with our diesels too using O/D and direct at peak torque and almost peak hp rpm of the Cummins.
