6.4L Hemi tow report - weights added
Towed 550 miles over two days. 5er is completely loaded to max gvwr, even had fresh water on board. I'm going to say it was about 12k#. I ran through hills, up mountain grades, into stiff winds and t...
Forum Discussion
Buck50HD wrote:
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One thing I found with my truck is that the 3.73 rear is ideal for holding highway speeds on moderate grades. 2nd gear puts it right at peak power (5200-5500RPM) at 60-65MPH, generating the full 385. A truck with 4.30 rear would be winding away at 6000RPM making less power. Plus, the trans probably wouldn't even allow it to downshift. So, you'd be stuck in 3rd(only 300HP) until you lost enough speed to downshift. In the mountains, it would have an advantage when speeds are power-limited to less than 60MPH. The Ford trans could use less spread between 2nd and 3rd.
The 6.4 Hemi needs a lower 1st and 2nd gear, even with the 4.10 rear. The 3.73 cripples it even more. At highway speeds, it's not possible to get full power. Despite the poor 1st and 2nd, 3-6th are about where you'd want them with 4.10's and have a nice spread.
Hopefully we'll see 8spd (or more) trannys in the future. I would like another gear between 1st and second on my Ecoboost, primarily for going down certain steep hills.
