Looks like there are two options for the 6.4L with automatics
66RFE and the Aisin
Both are 6 speeds, but which is better and why?
Any one have the specs for each?
The 66RFE hasnt been used in years, the replacement was the 68RFE which is considerably stronger. 120k normal fluid cycle, 60k severe duty cycle. It also has dual fluid filters, Dual face torque converter, Bandless clutches for simplicity and wear, and can lock the Torque converter in gears 2-6. Has a maximum torque input of 900lbs-ft torque.
1st 3.23 : 1
2nd 1.84 : 1
3rd 1.41 : 1
4th 1.00 : 1
5th 0.82 : 1
6th 0.63 : 1
R 4.44 : 1
The Aisin weighs in about 200LBS more than the 68RFE, is not available in the 2500 and has a 30k mile service interval regardless of use. Has dual transmission coolers, and an input rating of 1200lbs-ft torque. The Aisin also has a maximum RPM speed of 4660 RPM, so if it is paired with the 6.4L Hemi, peak horsepower from the engine is reduced to 370 horsepower, instead of the normal 410 horsepower at 5600RPM
1st | 2nd | 3rd | 4th | 5th | 6th | R |
3.75 : 1 | 2.00 : 1 | 1.34 : 1 | 1.00 : 1 | 0.77 : 1 | 0.63 : 1 | 3.54 : 1 |