4.56 gears???

[Farmer Rock]

so,i'm really starting to hate 3.55s for what I do. I am getting ready to do a clutch job and have been tossing around the idea of either a granny gear transmission with over drive from a international, or regearing the differentials.
I imagine regearing is best since it's 4x4, so if that's the case, I was thinking like 4.56 gears but am open to other ratios.
I really need a lower first gear and reverse, that's the main reason for this .
I should mention, this truck is a 93 CC 4x4 zf5 with 3.55 and auto hubs currently..
It is my daily work truck, and it gets loaded every day.
As far as the top end goes, I'll be happy as long as I can run 65, since I'm usually towing if on the highway anyhow.
Thanks

Rock

 

[Nero]

My dad's CC has 3:55, my CC has 4:10, my top speed is usually 65-70, but my towing capabilities are more than his. I'd say 4:10 is a good number.

 

[Cubey]

Hard for me to say, my 3.55 F250 is NA and my 4.10 RV is turbo. It's kind of a slog going up steep grades, even with 4.10. But my F250 has been up very steep grades too and it was just as miserable, while weighing far less and not being nearly as tall.

 

[TNBrett]

http://www.grimmjeeper.com/gears.html

Play around on there. If you mean what you say, I’d go with 4.56. On my truck 4.10 and 245/75-16 let’s me cruise 75 or 80 just fine

 

[chillman88]

I've occasionally wanted deeper gears on my dually than the 4.10s it has. I think for the way you're going to be using the truck it might be a good idea.

If you do much highway driving you probably won't like 4.56 gears, but I would think around the farm they would be perfect.

What about just using low range on the transfer case? Would that suffice?

For what it's worth, I've run 75-80 before with my 4.10s so 65 should be manageable with 4.56 although it'll scream.

 

[Farmer Rock]

I've occasionally wanted deeper gears on my dually than the 4.10s it has. I think for the way you're going to be using the truck it might be a good idea.

If you do much highway driving you probably won't like 4.56 gears, but I would think around the farm they would be perfect.

What about just using low range on the transfer case? Would that suffice?

For what it's worth, I've run 75-80 before with my 4.10s so 65 should be manageable with 4.56 although it'll scream.

Hey Chris, I don't do an awful lot of highway driving. Usually if I'm on the highway, I'm just hauling/towing cattle or equipment so I don't go faster than 65 anyhow.
My 6.9 had 3.55s as well, and I always had to use low range to start out, and then shift to high. This transfer case has one of them stupid shifters you have to push down hard to get in and out of low so it can't be floated on the go. The trouble is this is an everyday deal, multiple times, so I can't keep stopping everytime with a load to shift to high like my 6.9
It's a huge pain......




Rock

 

[IDIBRONCO]

You know, I think that I'm going to leave this one alone. This subject can cause as many arguments as "what kind of oil should I use?". If all else fails, write all of your choices down in a circle and throw a dart at them to get your answer. In my opinion, nobody can tell you what gear ratio to run or how to use your truck. There's going to be up sides and down sides to any choice that you make.

 

[david85]

From factory, my truck had 4.10 gears and a C6. Top speed was about 70 MPH, right up against the stock governor.

Then I ran my truck for many years with a 3.08s/E4OD combo and loved it for highway running. Towing was in 3rd (direct ratio) and 4th was for empty cruising. 2nd gear was also great for storming 10% grades on secondary highways (2nd gear would pull like a train right up to 55 MPH).

Now that I swapped to 4wd, I had to go with 3.55. I find the truck gets caught between gears and makes me miss the 3.08s. I can see how 3.55 would be a disappointment in a N/A truck.

The thing to remember is once you are "out of the hole" (above 20 MPH), your rear gearing doesn't matter that much. For taller axle ratio, you simply hold onto a gear for longer. For lower axle ratio, you have to up shift sooner, or you hit the governor and stop accelerating. But it sounds like getting a heavy load out of the hole is the problem here, so lower gears would help.

I personally wouldn't go with 4.56, because I still need to cruise on the freeway once in a while. But if you don't, then by all means, go low.

 

[Cubey]

From factory, my truck had 4.10 gears and a C6. Top speed was about 70 MPH, right up against the stock governor.

I've had my RV up to 75 before for a very short amount of time a time once before, and it could have probably gotten up to 80 if I had let it. It's turbo'd though, so that could be why. But still 4.10 and C6 behind it.

 

[franklin2]

No matter what gear you chose, you will still need to shift into 4 lo to use reverse backing a loaded trailer with the zf. Zf reverse is just too high for anything except empty backing and it's great for snowplowing.

You didn't mention your tire size, which plays a big role in the gearing also. If your tires are oversize, the 4.56 may be the best. I had the zf, 4.10's and 35 inch tires on my truck when I bought it, and it was borderline, you always had to downshift when pulling a hill, even empty sometimes. I now have closer to stock size tires on it and its like a different truck towing.

 

[Big Bart]

No matter what gear you chose, you will still need to shift into 4 lo to use reverse backing a loaded trailer with the zf. Zf reverse is just too high for anything except empty backing and it's great for snowplowing.

You didn't mention your tire size, which plays a big role in the gearing also. If your tires are oversize, the 4.56 may be the best. I had the zf, 4.10's and 35 inch tires on my truck when I bought it, and it was borderline, you always had to downshift when pulling a hill, even empty sometimes. I now have closer to stock size tires on it and its like a different truck towing.

Good point Franklin.

Also think about fuel economy. My truck has 4.10’s, is 2wd, non-turbo, has a C6, and averages 12mpg. Less when towing heavy. My truck needs 2nd on a steep grade to get up it. On the flats is fine.

4.56 would likely take me down to 9mpg on average. If you don’t mind that or perhaps being limited to cruising 55mph at 2,800 rpm on the highway. It’s going to tow a load likely better as long as it does not goof up via the ZF5 gear ratio.

You could try doing the rear first, go test, abort if needed to 4.10’s.

 

[u2slow]

I won't pretend to know the condition of your truck. I try to look for associated things that need addressing at the same time.

I can usually dig up 10.25" diffs in any ratio w/trac-lok for $100-200ish which is a bunch cheaper than a shop putting in a r&p. That means ubolts, so its a good time to consider if you need to tuck in a couple more leafs, overloads, etc. Get a few 2wd miles on it to see if that's the improvement you need.

Then you can choose to muddle through a front r&p swap on your own... or find a whole diff (or housing) with 4.10 in it already. If you find a 95-97 version, it has better brakes.

Another left-field idea.... if your trans is getting tired, look for a 96-97 diesel S-47 5spd. The ratios are bit better (deeper). There's also guys that take the 460 version (widest ratios) and drill it for the diesel pattern.

 

[chillman88]

Hey Chris, I don't do an awful lot of highway driving. Usually if I'm on the highway, I'm just hauling/towing cattle or equipment so I don't go faster than 65 anyhow.
My 6.9 had 3.55s as well, and I always had to use low range to start out, and then shift to high. This transfer case has one of them stupid shifters you have to push down hard to get in and out of low so it can't be floated on the go. The trouble is this is an everyday deal, multiple times, so I can't keep stopping everytime with a load to shift to high like my 6.9
It's a huge pain......




Rock

If you're having to use low range to get rolling I think you're going to want the lower gears. You're working it and not just cruising it around town empty. My vote is for the 4.56s for you.

I was thinking you just needed low around the farm, not thinking about starting out all the time. I don't usually use first gear unless I have a trailer on with my 4.10s. I've accidentally started out in third before

 

[Randy Bush]

With my 93 dually it has 4.10 and originally a close ratio transmission. Did not work good for heavy pulling. At the time believe when I looked into different rear gears was told 4.10s was could get not 4.56 in a F350. So ended up using a wide ratio trans out of a 4x4 and regeared mine. Has a real low now Have to shift as soon as get rolling. Note took the wide ratio gears out of 4x4 case and put them in my case.

 

[Farmer Rock]

Update....
This morning I towed an 8x8x18 12 ton wagon with 120, 100 pound bales..
This was by far the heaviest hay wagon I've had behind a pickup.
It had to be around 15k with the wagon.
I only had to take it like 8 miles, but that took 45 minutes..
I barely..... barely pulled the first hill in second gear, but the truck absolutely hated it, not to mention the black cloud that followed me along.
It was first gear the rest of the way, it just wouldn't pull in 2nd.
I do feel like 4.56 gears would solve this to a point..
I can't say I was disappointed with the truck, but definitely the gearing...
I wish I could find differentials with 4.56 gears used, but that's not going to happen, so do any of you guys have an idea on what a regearing job would cost?
Thank you guys for all the great input, I appreciate it.

Rock