4.56's With 33's And 4.2l
 

Hello All, I am trying to decide wether or not to put 4.56 gears in my truck. I have 33" tires with the 4.2L V6 and the 5-speed. Right now I have 3.08 gears and my truck is severely sucking wind. I know that there is charts and websites and whatnot that tell you rpm's and all that, but I am looking for anyone who has done this swap and how they feel about it. I pull a boat in the summer and haul the wheeler around all the time. I also do a little trail riding up here in Minnesota and would like the grunt of the much lower gears. Also, what other mods would need to be made to the differentials with the 4.56 gear swap? I have heard of carrier changes and stuff like that being required.

Thanks for the help,
Crotteau

I went with 4.56's with my 36" swampers. They run great but with 33" tires i would probably be running 4000 revs on the thruway. I would go with 4.10's

-Jon

going from 3.08 to 4.56? Thats a little drastic. You should stay around 3.73 or 4.10.

I have 31" tires and went with 4.30's. It does run at a higher rpm on the highway but not intrusive. I will be putting in a tach in the next day or two so I will let you know what rpm at what speed. I have the 4.6 L motor and the gears work well with this motor. Can't tell about the4.6l.

I figured that 4.56s will be a little steep with the 33"s I have now, but in the future I would like to run 35"s and I don't want to have to swap gears again. Does anyone know if this gear swap will require a carrier change as well? Also, what is available to correct the speedometer for the new gears?

Thanks,
Crotteau

I have the 4.2 auto, reg. cab short bed, and 4.56's with 32's. I ran 30's before that with the 4.56's. The 4.56's are good with the 32's and I plan on running 33's, but bigger than 32's will start pushing the motor out of its power band which I am not looking forword to. If I ever run 35's I will switch over to 4.88's. Any one who drives a 4.2 knows they are not fast off the line, but then the motor spools up and thats when it takes off. The lower gears let the motor spool up faster and not bog down when you shift, I have heard people whine about how fast the motor will be going with the gears changed, and slim to none of them are running a gear set up in any way considered extreme. My motor is not screaming down the road and I drive 70-80 going to school every day. With a 5 speed you have even more of an advantage with an extra gear thrown into the set up. I would go with 4.88's In my truck assuming to run 35's but with a 5 speed and considering some people still want to run a truck with stock or average gearing then go with the 4.56's and change the speedo gear.

Currently I run 31" and also have a ratio of 3.08. I can totally feel where you're coming from. Fortunately, I am having 4.11 gears installed at the end of the month. I can't wait. I decided to go with 4.11 gears in the front and rear as I am planning for the future where I will most likely want to get bigger tires. I'm not excited for the extra RPMs on the highway with my daily driver, but I'll sure do better on those hills. Oh, and of course when four wheeling. I'm also installing a Power-trax No-Slip. I don't know what I am going to do with myself with all these upgrades. :) Good LUCK!!!!

4.56 265/70R17=31" being almost bald
2400@70mph

If you want to go up to 35", you may need to upgrade your gears to 4.56. You have a 4x4 V6, 35" tires are going to suck up a lot of engine power. You should also consider some more engine mods to offset this.

Thanks for all the help guys, I think I will go with the 4.56's as I know that if I do the 4.10's I will someday wish that I gone with 4.56's instead. I do not drive enough with the truck on the highway as speeds greater than 65, so I think that overrevving will not be a problem. V6runner- what brand of gears did you use for your truck? Thanks for all the help guys-
Crotteau

I am running sierra gear which is made in italy and they have a fine reputation arround the area, in the 8.8 they do have a humming sound at 50 mph when putting on and off gas, I have had the some problem in another truck with percision gear also.
If I got a new set I would get ford motorsport gears from summit as they should be quieter. I have heard many bad things of the 4wheel parts genuine gear, very bad patterns, hard to set up correctly, mostly a guessing game.

4.10 gears will have a different sound than 4.56 so do not compare the two, 4.56 have a shorter contact pattern and will bring out more noise.

I'm in the same boat here, I was running 285's and felt the powerloss, compensated with chip, airaid etc. But know that gears are the way to go.

I'd like to know if you ended up getting the 4.56's
I'm seriously thinking about running 4.56's and some kind of LS in the rear with 285-75-16 tires. I have 4.2 v-6 5 speed reg cab

thanks

Maybe these can help some of you.

Ford drive ratios

Calculator

well after much deliberation, I've decided on 4.56's and a lock right hope to have them installed sometime in june.

regul8tor-

I hope it goes well for you. I am just a little too afraid that once I drop the cash on the new 4.56 gears, they will be too low for any highway use. I am also afraid of putting in 4.10 gears and not having enough gearing for the 33's? Maybe you will have to let me know how it goes for you. I probably will be torn on what to do for a while.

-Crotteau