Hi guys,,,,NJ here
Well my truck came with 17's on it and now i put 20's on it. It feels like it slowed down alot now???? My ? is' if my trucks pcm was programed for 17's would that do something to the trans and make it move slower .what could i do to correct it ?????[IMG]file:///C:/Users/MARC%27S%7E1/AppData/Local/Temp/moz-screenshot.jpg[/IMG]

 

did you put bigger size tires on and it and if so what was the original and new tire size because that is the big problem you might want to re due your gears to get that orignal power back..

 

The 20" wheels are heavier then the 17" wheels. If you want to get some power back I suggest trying a programmer. And if you want even more power then I suggest 4:10 or even 4:56 gears depending on what size tires you are running of how much power you want out of your truck.

 

go to 4.10 gears, you get the power back.

its all about getting them rolling

 

HI Guys I hear what u all r saying...The gears u r talking about 4.56 or 4.10 . I don't know to much about that kind of stuff .So how much will this cost and r their any other ways of doing this job ??? And the programmer u r talking about is it the 3815 superchips. If so I would love to buy one but every time I try and get one off the forums someone always beat me 2 it ??But I'll keep trying to get it amd see what it will do 4 me....ok thanks,,,marc

 

Yes the 20s are heavier than the 17s and will account for some of your power loss. But I'm assuming you went at least from 31.5" tires (the stock size that comes on 17's) to 33" tires (the stock size that comes on 20's). You have changed your "effective gear ratio" dramatically.
I'm also gonna guess you have the super lame 3.55 gears also. If so, your already **** poor gear ratio now act like a gear ratio of about 3.38. I can generate more power on my 10 speed (well not really, but you get the idea).

An upgrade to a minimum ring & pinion of 4.10 would get your effective ratio up to a decent 3.91 and an upgrade to 4.56 would give you an effective ratio of 4.35.

If you have tires that are 33" tall you could get by with the 4.10 gears. However, if you plan on ever getting bigger meats, don't think about anything but 4.56s.

The 4.10s will get you a little better power at the rear wheels than you had before, the 4.56s a good bit more. Combine a good tuner with the 4.56 gears and you'll have a whole new animal!!!

Don't let the "fuel economy nay sayers" fool you either. If your truck feels lame to you now, you are already pushing the pedal more than you did before to attain the same acceleration. You will GAIN fuel economy with the 4.56 gears IN EVERY DRIVING SITUATION except maybe interstate travel at speeds of 75+! It's the pressure on the gas pedal that increases fuel consumption. If you can obtain your desired acceleration with the pedal at 30% you will be using less gas than if the pedal is pushed to 60%, it's that simple.

Gears are fairly cheap, the rear set is $200 give or take and the fronts for an IFS probably around $225. You'd need an install kit with new bearings for about $100 and of course new fluids for both diffs at maybe $20. It's the install that will put a dent in the wallet. Don't skimp on the install, gears are not easy and to date, are the only mod in my truck that I've not attempted to do myself. Make sure someone who does differential work everyday does the install, not just any mechanic! I've seen some charge a grand for the install, but I've also seen some experienced guys do it "on the side" for $200 and do a good job. You'll have to find someone and get prices for the install.

If you can swing the $, do the gears. Most of us that have gone to 4.56 gears agree that it's the best single modification we've done to our trucks!!!

 

Hey I have 275/60/20 on the truck if that help with your ??? Also how can i check for gear ratio on truck .Were do i look for it??

 

look in the glove box or under the rear differential

 

Hammer if i have a 285 right now and i just bought a 6" suspension lift and 35" tires and i have 3.92 gears how bad will the performance change will be and i have a 2004 dodge ram qc 4x4 hemi 5.7

 

Thanks a lot i'm going in the garage to take a look i'll be back later have to go to the store 4 the old lady ....later 4 now .....marc