Truck has daystar level, 3 " rough country spindle lift and is sitting on 305 70 16s. My driving consist of stop and go in the city traveling to work of only about 4 miles and then some highway on the weekends. I tow a jet ski in the summer and notice the truck is a bit sluggish beginning but once its going their is no problem. I want to get some go from the truck off the line. Whats the most notable difference I will notice from running 4.10s? Currently getting 13 mpg driving decent.

 

What engine and transmission, and what gears do you have now?

 

he has the 4.6. IF you have the 5 speed, gear it. Auto you will be fine, unless you have 3.08's.

 

Here is a more specific way to look at it.
The 4.6 only begins to build real torque' quickly' just after 2000 RPM and gets to peak torque at about 3200 RPM.
Take a moment to trial this and see.
After 3200 RPM it still pulls hard to well over 4000.
The stock converter begins to hook up at about 12 to 1400 RPM.
This means the engine is hooking up to the driveline well below the good torque point of 2000 and makes the truck lazy until about 2000.
The 4.10:1 will help with moving the stall upwards a couple hundred RPM into more torque and continue to pull harder all the way up.
The 4.10 mutiplies the gearing torque at all RPM plus raises the RPM at all speeds.
The real way to do this is with a higher stall converter that begins good stall at about 1800 RPM.
Couple this with the 4.10 gear and you will need better tires off W.O.T. starts.
The other items are the speedo will need correction, fuel mileage may be even worse, shift points may change some.
Your call and depends on how bad you want this and the cost.
Good luck.

 

4.10 are a great gear for your purposes. What you have now depends on whether it is worth the cost.

 

Lariat is correct, its a 4.6. Tranny is auto and as far as gear ratio i have no idea what it currently is. What's the easiest way to find this out? Guys that are doing it will correct speedo and shift points with sniper tune.

 

The rear ratio code is on the door jamb in the AX box.

 

your tire OD is about the same size as mine. I've got the 5.4 and had 3.55 gears in the 9.75" rear. I went to 4.56s and picked up 2mpg and the driveability of the truck is much better. Mine is a 4x4 and has a 6" lift.

 

ok being an auto i'm GUESSING you have 3.55's

 

Couldnt find the gear ratio but the mechanics are going to check it out. Truck goes in on the 26th this mo. for 4.10s and programming. I cant wait to see how it runs! I will post up here the differences in feel and what i have noticed.

 

I would strongly consider 4.56. Especially is you have 3.55's now. 4.10 isnt enough to really make an improvement..

 

Cool jethat, i will talk to the mechanics on monday and see what they think. Thanks for the heads up

 

Or 4.30's since the truck is a 2wd

 

Thanks Canadian screw, alot of information in this thread so i will keep those in mind when i speak to my mechanic on Monday. These guys only work on Fords and are recommending ford racing gears, do these gears whine alot?

 

Just checked ford racing site and shows they dont carry 4.30s but do the 4.56s