I need help with choosing Rear End Gearing for my truck. I do alot of towing in city and highway and i just got 285/75*r16 put on my truck the gas mileage just went to about 10 miles a gallon. What do ya'll suggest to choose to help this problem with helping the tranny towing and the tire size issue?

2000 dodge ram 1500
5.9 Liter
285/75*r16 tires
Magnaflow exhaust and Cat
K&N airfilter

 

What gears are you running now? Your truck spec sheet should list the info, but if you do not have it look at the metal tag attached to cover plate of your differential. It probably reads 355, 392, or 410. Also is your truck 2WD or 4WD. With a 4WD you will have to replace both front and back differential gears or you will rip up your transfer case within minutes of engaging the 4 wheel drive.

 

4.10 to get you back to stock-like performace (i.e. the way it was with stock gears and stock tire size), and 4.56 for more of a performance gear (i.e. better towing and off-the-line performance, not quite as good on the highway).