I have been unable to decide whether to regear to a 4.10 ratio or a 4.56 ratio. I have a 03 5.4L 4WD, so 4.30's are out of the question. I know I need an 8.8 ring and pinion in a reverse cut for the front, and a 9.75 for the rear. However, I am unsure which ratio to choose. I have 35'' all-terrain tires on my truck that weigh ~65 lbs apiece.

I realize that 4.10's would get me back to a realized ratio of 3.73, and the 4.56's to a realized 4.30 or so. I have 3.55's in there now. I am not really regearing for power recovery, as I really did not lose much w/ the bigger tires, as I have the 5.4L and several bolt ons, so I am not lacking in the power dept. I am regearing primarily to protect the transmission. The truck is also a pavement queen mostly, and I could always use 4 Lo offroad I need more torque.
Does anyone have 4.10's w/ 35's? I realize that the general guideline is 4.56's, however, I am not looking to kill my top end by going too low, as I drive on the highway everyday.

Anyone w/ 35's and 4.10's please describe driving style, mileage, etc. The same goes for 4.56's. I'd prefer input from those w/ the 5.4L, 4WD, and auto, but anyone's input is welcome.

 

Not sure what you mean by "kill your top end"

 

ive given him a hard time on this before. He doesnt want to loose his highway MPG which unless he's going over 70 he should be fine, with 4.56's.

4.10's would work but its really not worth it to me to spend the money on 4.10's

Jon i know you will want to go bigger! I just know. Get 4.56's that way if you do decide to go to 37's or 38's you will be ok, even though 4.88's would be perferred!

 

I've got 4:88's now with 35's.

Trust me--you won't loose your top end. I can still get 12.5 mpg going 75 mph.
And the power is great!

It's too much work to go half way.

PM me if your interested in any info on these 4:56's I have for sale.

 

i wanted 4.88's I have a 4.2 and its turning 36's so 4.88's would give me some power back. But i was told that it was too much gear for my truck??? hows that possible?

 

I'm not expert but whoever told you that must be less of an expert than me.

I don't know why it wouldn't work. what you have it now? Gear ratio?

 

I have an 02 f150. I had stock 3.55s and then my transmission went out (i also have 35s) I went with the 4.56 and they feel awesome, I have actually seen a little better gas mileage and quicker pickup. I would say go 4.56 just to be on the safe side.

 

i have 3.55 LS

 

You may have to ask around the site a bit more to be sure but like I said, I don't know why it wouldn't work.

I have a 5.4. I'm not sure if you have a different ratio in the tranny?

Just a thought. I'm sure someone has done it though.

 

My mileage when from around 10-11 to 11.5-12.5 when i switched from 3:73's to 4:88s.

 

im pretty sure ill go with 4.88's anyways until someone can tell me why they wont work!

 

If I remember right I was running at about 1700-1900 rpm's at 70ish with the 35's and 3:73's.

Now I run at about 2500-2600 at those speeds with 4:88s.

Jyst FYI for comparison.

 

i'm interested in the difference too since i'll be in the same boat as minimonster here in a few weeks, except i have 4.6 and 3.55s. i could be wrong since i dont know a whole lot in the way of gears but, if hes doing mostly highway driving and he gets larger gears (4.56 or 4.88), wouldnt that put him at higher RPMs, and therefore...less mpg?

I do more in town driving, but i was leaning more to 4.10 gears too anyways since i don't do a whole lot offroading, just when i go hunting fishing camping and stuff, and that would bring me back to stock...but with this talk i may reconsider 4.56s. good thing i wont be able to get them for nearly a year, this could be a tough descision!

Cody

 

WE're only talking about a few-hundred RPM difference.
Your engine is nt working as hard with the numerically higher gears.

Imagine pedaling your bike up a steep hill.
In a tall gear, you aren't pedaling as fast, but it's REALLY hard work.

Now put your bike in a lower gear. You're pedaling faster, but it's easier.

 

my truck used to really work hard up even slight hills on I-70 and even down shift on the larger hills. (I know I'm in MO so don't give me any crap about the large hill comment.)


Now it never downshifts and usually the torque converter will stay locked the whole time even with the cruise on.

Some people on here say that even gears that are too short won't hurt your MPG too much because these motors don't use much more gas at 2000 rpm than at 3000 rpms. I don't know though.

and others say that low gears help in the city but hurt some on the hwy.

All I know is that 12.5 with a 5.4 with 35's is not bad.
and it drives a crapload better than it did with the 3:73's