I finally got the money saved for new gears. Around $700.00, for a 2wd. Now the question i have is exactly what is my best gearing for my needs. I have a 4.6 V8, 3:55, and 35'' tires. The shop is offering 4:10, 4:11, and 4:56's. I want to get my truck back up to speed like before the larger tires. Accelerate like stock or maybe a little faster. However my biggest concern is gas mileage. I dont want the 4:56 b/c that will be worse gas mileage than i have now. So its kinda between 4:10 or 4:11, not sure yet. I get about 10.5 city and 12.0 highway. I am mainly a city driver, stop and go traffic. So what is my best gearing for my needs? Gas mileage, greater acceleration, and overall best performance?? And with gears installed what kind of gas mileage can i expect to get?
Advice is greatly appriciated!
This modification is going to happen as soon as i have good advice for my application.

Thanks,
Jared

 

Installing 4:56 gears does not necessarily mean that you will get worse gas mileage. with 35" tires increasing to the 4:56 gear will more than likely increase your gas mileage from what you are getting now with just the 35" tires. now if you installed the same gears on a truck with the factory tire size then you would definately get worse gas mileage but an increase in acceleration. I think your decision should be between the 4:10s and the 4:56s. With the 4:10s you will be closer to your stock ratio and you will get normal gas mileage for one of our trucks. If you get the 4:56 you will see an increase in gas mileage from what you are at now but also see an increase in acceleration. I would also recommend getting a superchip to calculate for the tire size change and gear change(whichever gear you decide).

 

4.10 and 4.11 are the same. With your equipment, avoid disapointment and go for 4.56.

Ian

 

There is a conversion chart out there. I dont remember who had it though you may be able to search for it. On my 89 I have 36's and I run 4.56.

 

im gonna have to vote for the 4.56's also. as long as you dont have a heavy foot, your mpg shouldnt suffer.

 

So if i get the 4.10's i will be back to the stock acceleration and gas mileage? But if i get the 4.56 i will have increased acceleration but how much gas mileage difference between them? All i want is my power back and gas mileage to go from 10.5-11.5 in city to atleast maybe 14 or 15mpg...is it possible?

 

Another thing.. I know gears will get quick of the line but what about in the 50-65mph range and the 70-85mph range? How is the trucks accelleration at those speeds and how bad is the top speed affected by the gear swap, if the top end changes at all? I want as many details about a gear swap before i make this investment.

 

JSL1414,
You need to shop around. I just yesterday checked on a 410 gear change for my 2x4 and got a quote of $450 total. About 200 for the gears and 5 hours for the install.
If you are paying $700 then...

 

Lets assume you had 30" wheels and tires before with 3.55 gears. To get the same gearing you now need:

(35/30) * 3.55 = 4.14 or 4.10 to get back to where you were. But if you had 27" before you would need 4.56 to get back to where you were.

This ignores the huge inertia in the 35's. They are much heavier than the stock tires and will cause the truck to feel more sluggish when accelerating. Think of it as 4 large flywheels on your truck. This is why I said you should go to 4.56.

The ratio in the axle is determined by the number of teeth on the ring gear divided by the number of teeth on the pinion gear. This is why they come as a matched set. Depending on how you round it off, you might call it 4.10 or 4.11. If someone offers 4.11 or 4.10 as different items for your truck, I wouldn't buy from them, since they don't understand the concept.

Ian