Hello,

Next Spring, it'll be time to replace my 99 f-250, so I'm looking at towing capacities. How come there is 3500 pounds difference in the GCWR (F-250, manual trans, supercab, V-10) just by changing the axle ratio from 3.73 to 4.30?

I can understand that the lower ratio will give more ooph and allow it to pull harder, but does that mean the rest of the truck is capable of 20,000 pounds regardless? Since if I only tow about 2% of the time, and 98% of the time I would like the better mileage that I am getting with my '99 (3.73), it would seem to be OK to order the 3.73, and just take it easy when towing heavy loads. Heavy loads in my case approach the heaviest rating allowed on any of these F-250/350s. I don't need to worry about damage to any other parts from loading?

The '99 has been a great truck, but at 100,000 miles,it is really starting to show all those little annoyances that make me want to upgrade, for example, door rattles, spongy clutch, steering pull, dead horn, broken plastic ***** on the seats and radio, etc. Plus I think I've still got a couple of recalls unfixed.

Great forum you guys have here! John C

 

Not speaking from fact whatsoever, I would imagine there would be no concerns as regards other parts of your truck when speced with 3.73s. Ford doesnt use "tougher" or more capable supporting components for a truck based on the rear it has been speced with. Considering the low hole in the 6speed, I would imagine you wouldnt have any trouble at all towing what you tow. Yes, granted, it would pull better and be somewhat easier on your motor with the 4.30`s but if you are only towing 2% of the time, then I would think the fuel consuption shoud be your first priority and go with the 3.73 if that is what you want.

I would equate this concern to the differences between the F250 and the F350....there really isnt that much difference except that Ford gives the 350 a higher rating.

Of course, if you think you might want to swap out to larger tires and still do towing then go with the 4.30s hands down.

Whether you spec the 4.30 or the 3.73, all the other components will be the same

I went with the 3.73 for a number of reasons, one of them being slightly better fuel milage. One could make the argument that with 3.73s the motor may have longer life due to its more relaxed state (lower RPMs) at high speeds if you do alot of highway driving.

And that low hole on the 6speed is pretty darn low to get you rolling, after that let the momentum help you thru your next gears!