which rear-end ratio?

[Ron Bickel]

Looking to pull a trailer weighing 25,000-30,000 #. My '96 Powerstroke with 3.55 gears doesn't want to pull the load. My question is would 3.73 gears be adequate so that I can still get half-way decent mileage or will I need to go to 4.10 gears? Thanks.

[Rich_Kimball]

Ron, am guessing you are not serious right? Go get a bigger truck for that load as not even 4.10 will be enough. Neither are your brakes!

[SmokeyWren]

Originally Posted by Ron Bickel

Looking to pull a trailer weighing 25,000-30,000 #. My '96 Powerstroke with 3.55 gears doesn't want to pull the load.

Your truck is rated to gross 16,000 pounds max combined weight (GCWR). If you had the 4.10 axle ratio, the rating would go up to 20,000 pounds combined weight. Nobody with good sense would attempt to gross 37,000 pounds by pulling a 30k trailer with a 7k pickup that has a 20k GCWR.

Not even a 2008 F-450 pickup is rated to gross more than 33,000 pounds combined weight.

An F-550 with 4.88 rear axle ratio is rated to gross 30,000 pounds combined weight if it has the high capacity towing option. But to gross 37,000 pounds requires a properly equipped F-650 or F-750.

Another problem is hitch weight. Unless you are talking about a wagon-type grain trailer with almost no hitch weight, you're going to severely overload the rear axle and rear suspension and frame of your tow vehicle. A gooseneck trailer with 18 percent hitch weight when loaded to 30,000 pounds will put 5,400 pounds of road-hugging weight on your truck. So you'll wildly exceed the GVWR of the tow vehicle.

So simply changing the rear axle ratio in a pickup is not going to hack it. You need a much bigger truck to safely tow a trailer that weighs 30,000 pounds.