Gear Ratio
 

I have a Ford Expedition with a 5.4L 4x4 that is rated for a 6600 pound trailer with the differential ratio of 3.55 .
I have been thinking on changing my differential ratio for either a 3.73 or a 4.10.
As it is, when my speed is 100 KMH the RPM is about 1450.
What would be the RPM and the max that I could tow with these two differentials ?
Thank you

Re: Gear Ratio
 

I think the highest tow rating available on an excursion with the 5.4 is 7200 LBS. With the 3.73's you would be runnning 1525 RPM at 100 KMH with the 4.10's you would be running 1675 RPM at 100 KMH.

Re: Gear Ratio
 

I thought that was the figure that would come out, but isn't there some other figures to take in consideration when changing a differential ratio.
With a 4.10 ratio is the max trailer weight still the same ?

Re: Gear Ratio
 

according to Ford's spec's the towing cap is 7200 with both the 3.73 and 4.10 geasr I believe.

Re: Gear Ratio
 

The 3.73 gear is only 5% different.

The 4.10 is 15% higher.

Are you looking for better acceleration or just better pulling power.

Try pulling in 3 (drive) not OD.

Wannabe

Re: Gear Ratio
 

My first goal is better pulling power, but if I can get both.