2009 4.7L - 4.10 or 4.56 rear gear

09SilverRam · Aug 19, 2024

Ok, I’ve done some searches and I’ve seen 4.56 recommended a lot for 4.7 trucks, but I many of those people had larger tires. Getting ready to redo the rear gear and trying to decide between 4.10 and 4.56 for a truck with the stock 265/70r17 tire size and no plans to go larger?

I have a daily driver so don’t drive the truck a ton, and I tow a trailer once a month anywhere from 60 - 200 miles one way. Trailer currently weighs in at 5100, but has a GVWR of 7k and could reasonably weigh up to 6400 depending on what we put in it. It is a tall cargo trailer with the same wind resistance as an RV.

Right now in 3rd (4th on display in tow) gear (1:1 gear) I can run 2500 at 65, but I have to downshift to 2P (1.5:1 gear) to pull gentle rolling hills.

If I go to 4.10 I’ll be at 2850 to hold 65 in 3rd, and closer to 3200 with 4.56. 4.56 could open up using the .75 overdrive on the highway with 2400rpm at 66.

Unloaded on the highway Im looking at 2200rpm at 75 with the 4.10, and 2400 with the 4.56.

I kind of wish there was a 4.30 option but I don’t see one.

huntergreen · Aug 21, 2024

I’d stick with a stock ratio such as 3:92. This assumes you have the 8 speed trans, if not then the 4:10 ratio.

Jeepwalker · Aug 21, 2024

Yeah, IDK if I'd go too high. You can always baby it and get where you want to go, and not be a total gas hog the other 90% of the time.

Who says you need to 'race' your way there....

09SilverRam · Aug 21, 2024

huntergreen said:
I’d stick with a stock ratio such as 3:92. This assumes you have the 8 speed trans, if not then the 4:10 ratio.

545RFE, 3.0:1 first gear and .67:1 top OD.

I don’t get the benefit of the close ratios and ultra low 4.7:1 first gear.

A ZF8 in first gear with 3.21s has a 15:1 final drive ratio, a 545RFE with a 4:56 in first gear only has a 13:1 final drive ratio. From a towing performance perspective the 8 speed really provides an advantage.

metalchewy · Aug 21, 2024

My 2010, w/4.7 and 545RFE, and 3.92s tows just fine with the stock gears.

On hills I reach over and hit the tow/haul button. Uphill maintains the cruise control speed and downhill keeps it from coasting way above the cruise speed.

Early june,I put 1000 miles on it with a medium covered trailer and had no problems. Same mileage both directions, loaded and empty.

09SilverRam · Aug 21, 2024

metalchewy said:
My 2010, w/4.7 and 545RFE, and 3.92s tows just fine with the stock gears.

On hills I reach over and hit the tow/haul button. Uphill maintains the cruise control speed and downhill keeps it from coasting way above the cruise speed.

Early june,I put 1000 miles on it with a medium covered trailer and had no problems. Same mileage both directions, loaded and empty.

How much speed are you losing before downshift. If I just let it shift in tow haul and I’m going 65 cruise on (I use cruise all the time when towing on a 4 lane) when I start up a hill I’ve dropped to 55 - 58 before it shifts. I have to preemptively down shift so it doesn’t lug. I have not used JScan to compare TCC Slip intent vs actual when that happens.

This weekend I was at 10540 GCWR and it was just a dog trying to hold a gear on the slightest incline, which is why I’m looking at doing rear gears.

metalchewy · Aug 21, 2024

09SilverRam said:
How much speed are you losing before downshift. If I just let it shift in tow haul and I’m going 65 cruise on (I use cruise all the time when towing on a 4 lane) when I start up a hill I’ve dropped to 55 - 58 before it shifts. I have to preemptively down shift so it doesn’t lug. I have not used JScan to compare TCC Slip intent vs actual when that happens.

This weekend I was at 10540 GCWR and it was just a dog trying to hold a gear on the slightest incline, which is why I’m looking at doing rear gears.

If I let the cruise handle it, it's up to 5mph. If I keep an eye on it as I start on the hill it's about 1mph. I Wait till I see it drop a little and hit the button.

If I need to pass, I hit the button prior to even attempting to go around a rig.

caulk04 · Aug 21, 2024

Once upon a time I had an 02 Dakota with the 4.7 and RFE. I regeared it with 4.56 and wasn't upset about it. Installed a Detroit locker at the same time, also enjoyed that greatly.

I say go for it.

crackerjack1957 · Aug 22, 2024

I 2nd the 4.56 gears........not a daily driver & you tow so the 4.56 would help more than the others.
When its time to change tires you could get a taller tire & bring the 4.56 down to around 4.30 if you want.

62Blazer · Aug 22, 2024

09SilverRam said:
Ok, I’ve done some searches and I’ve seen 4.56 recommended a lot for 4.7 trucks, but I many of those people had larger tires. Getting ready to redo the rear gear and trying to decide between 4.10 and 4.56 for a truck with the stock 265/70r17 tire size and no plans to go larger?

I have a daily driver so don’t drive the truck a ton, and I tow a trailer once a month anywhere from 60 - 200 miles one way. Trailer currently weighs in at 5100, but has a GVWR of 7k and could reasonably weigh up to 6400 depending on what we put in it. It is a tall cargo trailer with the same wind resistance as an RV.

Right now in 3rd (4th on display in tow) gear (1:1 gear) I can run 2500 at 65, but I have to downshift to 2P (1.5:1 gear) to pull gentle rolling hills.

If I go to 4.10 I’ll be at 2850 to hold 65 in 3rd, and closer to 3200 with 4.56. 4.56 could open up using the .75 overdrive on the highway with 2400rpm at 66.

Unloaded on the highway Im looking at 2200rpm at 75 with the 4.10, and 2400 with the 4.56.

I kind of wish there was a 4.30 option but I don’t see one.

If the primary concern is towing performance, and you don't drive it that much empty, I would probably go 4.56. Empty it should feel pretty strong and be fun to drive. In top OD at 65 mph it's only 2,200 RPM which isn't that bad.
If "gentle rolling hills" needs 2nd gear now to maintain speed, I'm not sure 4.10 would be enough and you would still downshift to 2nd. That would really make the engine scream at over 4k to maintain 65 mph. 4.56 would give you a little more wiggle room before needing to downshift. But the biggest thing you mentioned is using the .75 OD while towing. 4.56 gears and the .75 OD would give you over 2,300 RPM at 65 MPH. I would suspect you could maintain the .75 OD cruising on flat ground and then only downshift to 3rd (1:1) for gently rolling hills, and still have 2nd gear available if needed for steep hills.

DILLIGAF · Aug 22, 2024

4.56

Daw14 · Aug 22, 2024

4.56 is an excellent choice, along with the tru-trac should put a smile on whoever’s drivings face.

Bmags · Aug 22, 2024

I think you'd be happy with 4.10s. But if you don't drive over 70 often you'd be with with 4.56 and stock wheels.

09SilverRam · Aug 22, 2024

Bmags said:
I think you'd be happy with 4.10s. But if you don't drive over 70 often you'd be with with 4.56 and stock wheels.

Coming from 3.55 I do think either will be a vast improvement.

Tominator223 · Aug 26, 2024

If there’s a 4:30 option maybe go that route.

09SilverRam · Aug 26, 2024

Tominator223 said:
If there’s a 4:30 option maybe go that route.

There is not that I can find.

crackerjack1957 · Aug 27, 2024

3:55 to 4:56 will be the most beneficial in towing.

2009 4.7L - 4.10 or 4.56 rear gear

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