2014 Ram 2500 6.4L Tow Review
Today I took my new Ram for its longest tow to date, a 350 mile trek through Ky and and the Smokey Mountains ending the day in NC. This was a good test with light to heavy rain all day, low visabilty ...
Forum Discussion
Actually, I had to verify my assumption so I ran the numbers on the 6.4 with 4.10's.
3rd gear = 3700RPM @ ~295HP (6.2 with 3.73 can make 260 in 3rd; 6.2 with 4.30's would be able to make 310HP)
2nd gear = 4830RPM @ ~385HP
So, the 6.4 with 4.10's would be in 2nd gear at 4800RPM to get 20,000 lb up a 6% grade at 60MPH.
Interestingly, the gear ratios work out so that the 6.4 in 2nd gear is making the same power as a 6.2 3.73 in 2nd gear (385HP). And, you cannot shift the 6.4 into 1st because it would be over redline. So, you can't take advantage of the full 410HP of the 6.4 when traveling 60mph. Plus, if you hit a steeper hill and have to shift to 1st, the HP at the ground at a given speed is almost identical between the 6.2 and 6.4 due to the engine speed difference (6.2 with 3.73's has a lower overall ratio than a 6.4 with 4.10's).
Another thing to note is that if they put a 6.2 with 4.3's against a 6.4 with 4.10's on a steep hill, the 6.2 is going to do better than the 6.4.
3rd gear = 3700RPM @ ~295HP (6.2 with 3.73 can make 260 in 3rd; 6.2 with 4.30's would be able to make 310HP)
2nd gear = 4830RPM @ ~385HP
So, the 6.4 with 4.10's would be in 2nd gear at 4800RPM to get 20,000 lb up a 6% grade at 60MPH.
Interestingly, the gear ratios work out so that the 6.4 in 2nd gear is making the same power as a 6.2 3.73 in 2nd gear (385HP). And, you cannot shift the 6.4 into 1st because it would be over redline. So, you can't take advantage of the full 410HP of the 6.4 when traveling 60mph. Plus, if you hit a steeper hill and have to shift to 1st, the HP at the ground at a given speed is almost identical between the 6.2 and 6.4 due to the engine speed difference (6.2 with 3.73's has a lower overall ratio than a 6.4 with 4.10's).
Another thing to note is that if they put a 6.2 with 4.3's against a 6.4 with 4.10's on a steep hill, the 6.2 is going to do better than the 6.4.
