i have a 98 f150 4x4 and i have stock wheels and tires on it. i am having to replace my ring and pinion gears and was wondering how to determin what i should do. should replace them and keep the 355 gears or put something else in there.
i plan on someday getting some 33" tires with rims and ocasionaly pulling a trailor once in a while. i dont know much about gears so all the info is greatly appreciated.

 

You said you're having to replace the R&P. Is that just the rear? or both? If it's just the rear, remember that if you decide to change the ratio you have to do the front to or you won't be able to use your 4x4. And remember to replace both is gonna run you double what it would to just replace the rear.

If it's both and you're looking for more power, or even if you want to add 33's I'd suggest putting 4.10's in it. Stepping up to 4.10's isn't gonna cost you much more, if anything.

You're gas mileage will probably go down a bit. If you're willing to lose a bit you will gain quite a bit in the power/towing cabability, especially if you decide to put on 33's.