Rear end gear question.
 

Ok, I have a 2007 Ram 1500 with the 4.7 liter. Love my truck and don't want to replace it. Bought a toy hauler and now I'm wanting to replace the rear end gears with what's best for towing. Im not sure which ones to go to. I think mine has the 3.55 in it. Can anyone help?

What size tires are you running?

35x12.5s

Also any engine mods I can make for more horsepower.

4.56 gears...... I bet it's a real dog with 35's, and 3.55's......

As for the engine, think I would start with a tuner.......

So, can I just replace the gears in rear end or do I have to do the front too? Actually doesn't do to bad. Also read that i could gain horsepower by removing the fan and clutch and replacing with an electric one.

You have to do the front as well, if you want to be able to use four wheel drive.... otherwise, things break. :) Gets expensive REAL fast.

Isn't there already an auxiliary electric fan on your truck? You can eliminate the mechanical fan, but, it really doesn't get you much.

Idk. I'll have to look. Someone said could add 10 hp?

What kind of tuner do you think would be best?

For the older trucks, SCT tuner from Hemifever, or Flyin' Ryan are the most popular, I would expect that either of them would have something for the newer trucks as well. Check out their respective websites, and see what you think.

No idea how much power the mechanical fan actually takes up. Question becomes, how much money do you need to spend to recover that 'lost' horsepower..... Lots of folks make eFans for dodge trucks, most of them run in the hundreds of dollars..... there are cheaper solutions...... sourcing a fan from a junkyard, and doing your own wiring, etc..... reliability, and not confusing the PCM becomes the primary concern there. (yeah, on some newer trucks, the mechanical fan clutch is actually controlled by the pcm.......) Guess it depends on if you want to spend the money on someones already developed system, or, time and effort on setting up your own.