OK, this week the gear swap is taking place. Currently I have the following:

1. Auto
2. 285's on stock rims
3. 3.55 gears
4. I tow a 4k trailer weekly

I am on the fence on 4.10's or 4.56's. Couldn't find for 4.27's for the 9.25 or I would split the difference. I drive 60MPH daily and 70-75 when on the highway (1/3 of my driving). I'm looking for power but don't want to be crippled by signifigant MPG reduction. I may go to 35's in a year or so.

Anybody toy with 4.56's on 33's? What can I expect? Should I go with 4.10's? Thanks.

 

If you are considering 35's in your future, go with the 4.56 gears. Even with 33's, you will only be bumping engine rpm by 2 to 300 at 65mph. The towing you do would be another vote for the 4.56's........

 

I used to tow a 5500lbs 5th with 3.92 and 33 tires but not on a regular basis, it worked ok not great but ok. If I was to use the truck for towing again with that weight I would go 4.56 for sure.

In your case I would go 4.56 it will just make everything ezer on/for the truck and you.

 

If you're doing it anyway.... personally, I think 4.56 is the way to go, costs being the same for either one..

the ONLY complaint I have about 4.56's- the shifting is freaky sometimes, and you can't program it away.. on an average start I'm out of first around 10mph, touch second and into third before 30mph, torque lock, then fourth about 45ish, and into torque lock so quickly it feels like a continuous shift from 3rd t/l to 4th t/l...

when I'm into it pretty hard, though, there are no weird sequences.. it does like it did w/ 3.92's..

 

are you running 33 or 35" tires... with the 35" the drivetrain should act pretty much stock since the loads on it and rpms are going to be about the same as stock...

With 35" tires 4.56 is the way to go and will net you the closest to stock mpg

With 33" tires 4.10 is the way to go and closest to stock for this tire size especially if your concerned about MPG.

If you really think you will go with 35" in the future or you do a lot of towing 4.56 is the better option.
I have no issues with 4.56 and 35" tires... when the truck is running right I average 12mpg.

 

I'm running 35".. the shifting thing is only under light load.. when I goose it, all gears bite in.. when I pamper it, the added torque simply doesn't need the lessor gears..

 

I bet thats likely due to your other mods giving you so much more power over stock.. 35" tires and 4.56 gears is really the same ratio as stock ... just as 4.10 and 33" tires would be and 31 with 3.92...

 

456 it is. I do plan on 35's soon. Short term I think I will be tall. Long term I should settle back into stock. If my calculations are correct 245's with 4.10's is 100 RMP less than 33's and 4.56's.

 

I ran the 4.56 with the 265/75/16 and it wasn't too bad. With the 285's its about right for me. Gas mileage is bad no matter what I do! With all my mods I get about 11mpg highway or town.

 

I went with the 4.56's and get her back tomorrow. Put new pumpkin covers on with magnetic drain plugs so future drains will be easier. I'll give her a hell ride after the new gears are broken in, then report back.