Difference between 4.30 & 3.55 gears
My 2011 F-350 has a 3.55 geared rear end. The new 2017 F-450 only comes with a 4.30 geared rear end. Basically the same engine (6.7 turbo diesel). Does that mean better or worse fuel consumption...
Forum Discussion
Just commenting on the diff ratio topic...
Most all OEM diff ratio's are about 10% apart from one to the other...going up or
down in ratio
Meaning that there is an approx 10% difference in torque multiplication between
ratios
So going from 3.55 to a 4.3 or about a 20% difference in torque multiplication.
20% more if going from a 3.55 to a 4.3. 20% LESS if going from a 4.3 to a 3.55
Many times...going to a higher numeric will increase MPG a bit...as
the ICE isn't working as hard...even though it is spinning faster
There are many, many other factors and why sticking to just the diff ratio on
this thread.
Most all OEM diff ratio's are about 10% apart from one to the other...going up or
down in ratio
Meaning that there is an approx 10% difference in torque multiplication between
ratios
So going from 3.55 to a 4.3 or about a 20% difference in torque multiplication.
20% more if going from a 3.55 to a 4.3. 20% LESS if going from a 4.3 to a 3.55
Many times...going to a higher numeric will increase MPG a bit...as
the ICE isn't working as hard...even though it is spinning faster
There are many, many other factors and why sticking to just the diff ratio on
this thread.
