Someone answer this question please. I want to get a 6" Pro Comp lift for my 04 FX4.
Is it absoluley necessary to change the gears. I mean if you get the lift and bigger tires, am I going to have all kinds of check engine lights and stuff come on. Reason I am asking, obviously, there goes your warranty, so forget bringing it to the dealer.
Someone who has lifted your 04' and replaced the tires please let me know. Thanks.

 

You want the simple soultion? Buy a Superchips Micromax tuner. Not only will it give you more power, but it has a function built in to correct the speedo for different gears and tire sizes.

 

Hi, I have the 6" PRO COMP lift and 35" tires. No, you do not have to do anything to the gears after the lift. I have been running my truck with the stock 3.55's for about 6 months. The only problem I have experienced is the transmission feels like it its searching for the proper gaer to be in because the speedometer is quite off. These problems can be fixed with any one of the programmers on the market. If you are going to be towing anything at all you might want to be ready to spend money on new gears or plan on having transmission problems down the line.

 

The warranty is not voided either unless the lift is the direct cause of a failure.

 

yahh the waranty still covers everything that couldn't be blamed on the lift. I had a lifted truck and still had the warranty to fix some problems. So if your supension cracks its coming out of your pocket.

 

I have the 6" Pro Comp lift and the 35's on mine as well. I'm running the stock 3.55 but I was told that the 4.10 would give me better response in the powerband, meaning that I could get to top speed quicker then using the 3.55 rear end would.

Is this so?

 

Yes. You need a lower pinion to gain back the mechanical advantage you lost when moving to the bigger tires. You could even go as far as 4.56. I ran 4.10s and 35"s with a C6 years ago, and it was a good setup. The additional gears of the new trannys would make 4.56 a better setup. Both will be much better than the stockers though.

 

thanks so much Rich,

Is there a good reputable place to get these differentails at? And what would be a decent price ? I also would imagine that I would need to do both front and back (4x4) right?

 

I have a 04' SCREW with an 8" CST lift and 35" tires. The stock 3.73 gearing seems fine, since the truck has quite a bit of torque. I also added the predator and that made all the difference in the world. In the future I may be doing some heavy towing and if so will swap to 4.56's, but for now no problem at all.