PerryB

Just thinking out loud here, and maybe I'm full of it BUT, I'm having doubts whether it was made in a 5-lug disc brake configuration for the f150 - in 4.10 I mean.. If it was, they probably represent a pretty small share of production. He better start looking now!

Streetwiseguitar

I'm gonna price out how much the shop would charge to change the gears if I couldn't/don't come up with an axel. 4.10, going by the calculator, seems like it would make sense ----IF I change from 3.55.

raski

Unless you are going to do some towing, I would stick with 3.55. Your mileage is going to suffer, no matter what some may think.

PerryB

The vast majority of the mileage hit is going to come from the larger/heavier tires. That falls into the category of pay-to-play. The gear swap will have a small impact on fuel economy, and a huge impact on power and driveability.

Streetwiseguitar

I'm trying to drive the truck differently than I was driving it originally. If I just operate the first 3 gears in a slightly higher rpm, I'm noticing the truck responding better. Thnx for all your input!

tagoo

Because you have a manual, the advise from those with automatics doesn't always apply.

There are a couple of other reasons you may want to consider lower (numerically higher) gears when you have a manual transmission. First, with the larger tires, you will find that you need to slip the clutch a little more to get rolling. I really noticed this when I put 35" tires on my 5 speed F150. My guess is that with taller tires, you will go through your clutch faster if you leave stock gears in the differential. Also, you may have noticed that it is more difficult to drive as slowly as you used to be able to do with your shorter tires (think parking lots). Lower gears will fix this too. Automatic transmission don't really have either of these problems as the torque converter of an auto is well suited to addressing those issues.

I've been driving my 4.6, 5 speed, 3.55 gear, 35" tire truck for about 2000 miles. Everything is fine once you are underway as you can put it in whatever gear makes sense at a given speed. But, the increased need to slip the clutch and less low-speed control has caused me to order 4.10 gears. Just a data point. It may or may not make sense for you to do the same.

On a separate note, many suggest the 4.56:1 gear ratio with 35" tires, but again, the manual transmission is a different animal. The manual only has a .8 overdrive gear ratio where the auto has a .7 overdrive gear ratio. This means if you go to 4:56 gears you will really be spinning the engine at freeway speeds with the manual while the auto will be running at significantly lower rpm. Not that you asked, but it is just another situation where the group's wisdom doesn't always apply to manual transmission trucks.

Streetwiseguitar

Ok - after having driven the truck a LOT now, I'm thinking what you're thinking. The size tires are having a huge impact on even slight interstate created hills (I'm in Miami - no hills). I'd imagine the motor is working hard and drinking tons of fuel when there's even a slight grade. I'm pretty convinced 4.11 is what I'm going to do. Any recommendations on the gear kit I should use?

Streetwiseguitar

NOW (that I've driven a ton) I'm feeling a totally kindred spirit with you!What kit did you go with?

OhioLariat

Before paying to replace the gears in yours, I still suggest calling some yards to see if they have an 8.8 that's compatible with your truck with the 4.10's already in it. As I stated above,I believe it will have to be out of a '98. MUCH easier, less expensive, and you might be able to upgrade to disc brakes.
..

Streetwiseguitar

When you say "an 8.8 that's compatible, etc.) do you mean just look for a 1998 F150 rear end? What is the arbiter on whether or not I'd be able to upgrade to disc brakes?

update: I did a parts serach at my local junk yard and 1999 is the date that came up w/ disc brakes. So.... (newbie question alert) will the yard pull the rear end for me?