I just traded my 2000 Viper towards an 09 2500 Megacab 4X4 6.7 with 6 speed auto and 4.10 rear end. My question is, is top gear on the new 6 speed auto a higher ratio than the top gear on the 4 speed auto on my 06 Megacab 5.9. My 06 had the 3.73 rear end and I'm wondering how the rpm's will compare at a given speed like maybe 65mph.
I'll be putting the 06 up for sale as soon as I pick the new one up at Pearsons in VA.
Thanx, Mike.

 

6th gear in a 68RFE is .61 or.60, compared to .69 in a 48RE. Even with 4.10's there is a decent cruise gear.

 

The info, assuming tire size is 235 x 80 x 17, at 65 mph.

48RE 4th gear ratio 0.690 @ 1800 rpm (3.73)

48RE 4th gear ratio 0.690 @ 1950 rpm (4.10)

68RE 6th gear ratio 0.625 @ 1750 rpm (4.10)


Dave

 

Wow, you guys are good! Thanx for the info, Mike.