F350: 4.30 or 3.73 Gears

SolidAxleDurango wrote:
He will be cruising at higher RPMs with the 4.30.

I'm extrapolating a little bit, and didn't clarify. With the 4.30 gears and being able to stay in 6th gear, he will have lower RPM's than with 3.73 and being in 4th or 5th gear.

double post

OK, I'll put in a little more information this time.

Yes, my 3.73 gear pulls my 12,000 lb. 5th wheel just fine and I run in 5th at 65 mph its about 2200 rpm

Sometimes with a strong head wind (15 mph) I need 4th, that is @ 3000 rpm

If I had the 4.30 gear, It would be @ 2500 rpm in 5th at 65 mph and I would most likely never need to use 4th to cruise.

I agree, once you start going to the lower gears climbing a hill, 4.30 doesn't magically procedure more torque when you are in a gear other than 1st.

Good read here:

http://www.ford-trucks.com/forums/1244843-need-help-choosing-the-3-73-or-4-30-axle-ratio.html

Thansk to all that have replied. I appreciate your knowledge !!

RCMAN46 wrote:

Chuck_thehammer wrote:
I would like the 4:30...


2 wheel drive 3:73.. very towable..

the 4:30 would allow a higher gear going up hill.. less rpms
engine is fine at 4,000 rpm's.. but body, sound, vibrations..

my opinion

The 4:30 will not allow less rpms going up a hill.

If climbing a hill requires x horsepower then the the engine will have to turn y rpm to make that horsepower.
Thus same rpm regardless of the rear end ratio provided you have a transmission that will allow the required rpm. The newer 6 and 8 speed transmissions do this very well.

There is nothing wrong with using 6 th gear with a 4:30 and 5th gear with the 3:73. The final gear ratio to the rear wheels will be very close.

Rear end Gearing does not make more power.

NOT more Power.. more mechanical leverage.
and it will lower the rpm's SOME.

why do you think some bigger trucks have 2 speed rear ends??
I used to drive a White .. 5 speed transmission and a Eaton 2 speed rear end. I wish pickups had 2 speeds...

Since no 4.88 is offered get the 4.30 ratio.

No brainer..... take the 4.30s if towing that load. It could do it with the 3.73 but it will be much more enjoyable with the 4.30s. I just started hauling around 11K with 3.73s and am seriously considering a re-gear. My dilemma is that Ram only has 4.10s or 4.56s.

RCMAN46 wrote:

Chuck_thehammer wrote:
I would like the 4:30...


2 wheel drive 3:73.. very towable..

the 4:30 would allow a higher gear going up hill.. less rpms
engine is fine at 4,000 rpm's.. but body, sound, vibrations..

my opinion

The 4:30 will not allow less rpms going up a hill.

If climbing a hill requires x horsepower then the the engine will have to turn y rpm to make that horsepower.
Thus same rpm regardless of the rear end ratio provided you have a transmission that will allow the required rpm. The newer 6 and 8 speed transmissions do this very well.

There is nothing wrong with using 6 th gear with a 4:30 and 5th gear with the 3:73. The final gear ratio to the rear wheels will be very close.

Rear end Gearing does not make more power.

^^^^^ at least someone gets it!!! :B

spoon059 wrote:
I'm with the others, the 4.30 gears will make your pulling experience more favorable. Empty around town should be about the same mileage. Empty on the highway will get slightly worse mileage with the 4.30 gears. Towing, that lower rear end will give you more grunt from a stop and have you cruising at lower RPM's..

He will be cruising at higher RPMs with the 4.30.

Chuck_thehammer wrote:
I would like the 4:30...


2 wheel drive 3:73.. very towable..

the 4:30 would allow a higher gear going up hill.. less rpms
engine is fine at 4,000 rpm's.. but body, sound, vibrations..

my opinion

The 4:30 will not allow less rpms going up a hill.

If climbing a hill requires x horsepower then the the engine will have to turn y rpm to make that horsepower.
Thus same rpm regardless of the rear end ratio provided you have a transmission that will allow the required rpm. The newer 6 and 8 speed transmissions do this very well.

There is nothing wrong with using 6 th gear with a 4:30 and 5th gear with the 3:73. The final gear ratio to the rear wheels will be very close.

Rear end Gearing does not make more power.