I'm getting ready to purchase a F450 4X2 6.0 auto. I'm going to be pulling a 28' tandem dually gooseneck with a GWR of 18,000. In the past I pulled this with a '96 F350 4X2 with a 460 cu.in. manual transmision and 4.10 rear end. DOT scales has weighed me at 26,300 GCVW. That truck has pulled the load pretty good even though I know it is overloading it.
Ford offers a 4.30 or 4.88 rear end for the F450. I will be using the trailer a couple of months in the spring and a couple of months in the fall over a wide range of terrain. Other times the truck will be used just for carrying supplies. Will the 4.30 rear end do the job or will it be best to go with the 4.88 and sacrifice some fuel mileage without a load? My old truck would get 6-7 MPG loaded and 13 MPG empty.

Thanks!

 

I've been calculating gear ratio effect from tire size increase lately, so I have some of the info handy that may help you. I test drove a F-550 with the 7.3 diesel and 4.88 gears last summer. Had lots of power, but was high in the RPM's cruising at 65 MPH, but not too bad. There was no reciever hitch on the truck so I couldn't tow with it during the test drive.

The 5 speed Torqshift auto has a 0.71 overdrive, the same as the E4OD. The F-450 brouchure stated a 225/70/19.5 tire size, so the tire diameter would be 31.9". At 65 MPH in overdrive the 4.30 gears will require ~2100 engine RPM and the 4.88's ~2400 engine RPM. This higher RPM will burn more fuel, I am estimating about a 1.75 - 2 MPG loss.

I tow a 9900# 32' travel trailer with my F-350 V10 with 4.30 gears, and have seen the same acceleration and ability to sustain speed when climbing hills as a 3.73 geared 6.0 liter F350 towing the same trailer. Knowing that you will be pulling a heavier trailer, I would opt for the 4.88 gears myself. There are also dual range auxilliary transmissions available from Gear Vendors or US Gear that could overdrive a 4.88 gear ratio to a 3.90 effective ratio. They are about $4000, but then you'd have the best of both worlds.

Hope this helps,
C.A.

 

With the 4.88's, you sure wouldn't know anything is back there. I think the 4.30's would be sufficient for the job though. You want to make sure you don't get too much gear. The 4.88's would be more for rock crawling.

 

Yes, make sure not to go rock crawling with your 2 WHEEL DRIVE F450 with 4.88 gears...

 

If it was my truck I would go with the 4.33s if you go with the other you might be tacked out at a higher RPM all the time that means more ware and tare. Good luck let me know what you get I am thinking of a 450 myself with 6.0 6spd 4x4 to pull my trailers.I have a 2000 F350 with 4.10 7.3 power stroke 6spd 4x4 never again will I buy a 4x2 to pull trailers. 4X4s are more stable on the road. And if I go out in a feild I do not get stuck like my old 4x2 86 F350. just a little food for thought. Good luck.

 

I have been pulling a 5ver that weighs around 17000# with a 02 450 with the 4:30 and Im here to say I have had no problems.I pull from the east to the west coast.I had the same question when I was buying mine and the salesman told me it depends on how many times I pull that kind of load and how much I drive empty.The fuel milage is what he was reffering to.