Hey fellas. I love my ride. I have all kinds of things done to it. Now it's time to give her some more gear along with a stronger transmission. Today I had my 315-70-17 BFG AT's put on and they rock! But with my 2" cam kit installed on the front end, and the almost 9% taller tire....My trucks in need of more power. I also plow snow, and with 88K I am sure my tranny is going to need some TLC at some point in the near future.

OK. Here it is. I have 3.55 Gears in the rear end. My estimate is with my tires now, I have an actual gear of around 3.30.

With that said, I want an actual gear ratio of around 4.56 I think...and I would like to do it through the transmission instead of the rear end. Is this possible? Lower tranny gears? I would think so.

Also, while my mechanic is in the transmission, I would like him to beaf it up. I don't want to EVER have to put a transmission in this truck again. I am good to my tranny's...I neutral drop, I always warm them up before hammering on it and most importantly, I do the 30K service.

In a nutshell, what I am saying is I want more acceleration, and a stronger transmission,. Maybe what I want is a differant trans? This is why I ask!

The person that would be performing the work is a master ASE mechanic and has been mine for years. He does engines, tranny's, rear ends, diesels, ANYTHING. he's the man, and he's 40$ per hour for labor. I mentioned both of my items here to him and he said that we can do it. We are going to get together in the spring time here after the snow season is done and get it done. I am just trying to do some research before hand to so whats up.

O yeah. It's a 70rw trans or whatever they call them. The general purpose one. Not the beefy one. Also I got a 5.4 2v motor.

 

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The first gear in the 4r70w is the only one that is lower than what would be in a more normal gear spacing such as AODE/4R70. Thats the W designation.
You need to go with axle gears to get more pulling power.
Next, the 4r70w can be rebuilt near bullit proof for alL intent by going thru all the internals and bUilding with some different parts like better clutches and bands, higher capacity fluid pump, bearings, valve body rework or replacement and consider a better converter with at least a double disc lock up and possibly a lower stall if that is what your after or a higher stall depending on what you want to do with the truck. In my case it was towing power and not hi rpm take offs.

I have a custom 4r70w 4x4 in my 02 behind a 4.6 and it cost a bundle to build by a well known trans shop.
Hope you got a big piggy bank.
Good luck.

 

HI!... Actually the 4R70-W has two gears that are lower. 1ST and 2ND gear.

**4R70-W**

1ST - 2.84
2ND - 1.55
3RD - 1.00
4TH - 0.70 (O/D)


**AOD-E/4R70**

1ST - 2.40
2ND - 1.47
3RD - 1.00
4TH - 0.667 (O/D)

 

It isn't possible. There are no lower gears available for your trans, and the 4R70W has a 2.84:1 first gear. The only other trans that could fit in that truck is the 4R100, and it has a 2.71:1 first gear.

 

Is your current tranny bad?

Do you have a tranny cooler in addition to the factory one?
If not, adding one can extend the life of your tranny.

Do you have an aftermarket valve body?
If not, this can also extend the life of it.

You might want to consider re-gearing the differentials first. This will not only multiply torque to the rear wheels, but it will also significantly reduce stress on your tranny, potentially extending it's life.

Just some food for thought. A dissenting opinion, if you will.
I wouldn't crack the tranny case unless I was going to build it out, but I won't even think about it until/unless my current one fails.

 

Thanks fellas. I see your points.

Now I guess I have to ask. Whats the cost for a nice 4.56 gear set thats LS for the rear, and I suppose I would just use a standard 4.56 in the front.

Also, anyone estimate the hours of labor on each end of the truck?

Thanks for the input. So I guess I cannot lower the trnny gears. That sucks. But I guess the front and rear end will have to do.

I want that feeling back I had when the truck was stock. I want the truck to do 80MPH up and downhill on the e-way in O/D without kicking down and without me having to keep the peddle half way to the floor. Are 4.56 gears what I want? I wonder how bad it's gonna kill my gas mileage too.....Thanks again.

EDIT: Also, NO my current tranny is just fine. Other than a squeak at WOT shifts and it not switching from reverse to O/D not really fast thats all.

 

I run 4.10s on a 31.5-inch tire (285/6-R18)

Your tires are really close to 35 inches, and most folks think 4.56 are good for 35s.

Your mpgs won't change IMHO. Lots of guys have re-geared, and most posts claim no noticeable difference, up or down. But you'll get a lot of your power back.

Here are my RPM at various speeds. I don't think you'll too far off from this.
https://www.f150online.com/forums/sh...d.php?t=263323

I don't think 4.10s are a good choice for your taller tire.
4.56 is the next step up.

 

Thanks for the input. I see your point. I checked out your pics. Actually, I am not close to you right now at all. I checked mine, and with GPS doing 70MPH I was at 1750RPM. Now, the truck CAN hold that speed up and down hill without kicking down, but there is almost NO acceleration unless I kick down.

This brings my most important question to mind, will 4.56 gears give me back my no kick-down 4th gear freeway accleration back? Thanks again. I know i'm a question askin fool and I appreciate the help!

 

Here is another way to look at this.
With 3.55 gears times .7 OD ratio, the final effective "axle" ratio is 2.485 to 1.
With 4.56 gears times .7 OD ratio, the final effective axle ratio is 3.192 to 1.
Now, what the effective ratio is between stock tire circumference and your new tires is, would have to be figured to see if you will arrive at a better final overall effective gear ratio than the stock OEM gearing.
The tire mfger's spec has to be used to figure this difference.
Then you will know exactly what to expect from any changes.

Said another way, you change to lower gears then take some of it back with larger diameter tires. Where you end up has to be figured out mathmaticly.
Good luck.

 

My math tells me if you put 4.56's in there and change nothing else, you will now be doing 2250 rpm in 4th at 70 instead of 1750. This sounds a lot closer to the torque peak and you should get considerably better no-kickdown response. This does sound like a lot of work and expense just so you don't have to kick it down or lock it out of overdrive. If you take it out of overdrive with your present gearing, it will be doing 2500 rpm at 70. My math does not take into account whether the torque converter is locked or unlocked. A gear change should not affect low speed gas mileage, but on the highway it will probably suck down a lot more gas - especially if you try cruising at 80 or higher. My V6 2wd with 3.55's and stock tires gets 20 mpg at 65 but it drops to 16 at 80+. That's worse than my around town mileage.

 

I meant to say that you'd be close to this after you did the swap to 4.56 gears

Most folks who have done gear swaps till tell you the same thing: MPGs haven't really changed. Check all of the posts where people have done this...I haven't found anyone who wasn't happy wit the swap, and I haven't found any that report worse mileage.