I have a 2002 f-350 psd lifted with 37 inch tires,with 3.73 gears and pull a 25 ft toyhauler,should i re gear it,it seams a bit sluggish and does not pull the trailer as well as I thought it would.Any help would be appreciated

 

You probably need to regear just for the tires sake, your 37's are roughly 6 or 7 inches taller than stock. I would imagine 4.11's would put you where you need to be, and regain some of that lost performance.

 

will that hurt or help my milage,I assume it will help

 

Those tires are going to hurt your mpg no matter what you do. Even Houdini could not get around that simple fact. You gonna have stuff like that to look cool with, you gonna pay. Simple as that. 4.11's will give you back your pulling power, but they're going to effect your fuel use. Like I said, you play, you pay. Jeez, it even rhymes.

 

It isnt just changing the gears that are gonna affect your mileage. Your mileage is already affected. It is just because your speedo is off by 5 or 10 mph that you dont really notice it. If you got something like a truspeed and recalibrated everything you would not notice much difference when you chage gears, except your engine would not strain so hard.

 

You change the gears and you will have worse mileage. If you tow alot then you might want to change gears. You will also have higher EGT's with the stock gears.

You can always add more power to deal with it!! LOL...