4.10 Gears.

[RHamill]

I didn't know you can drive 0 mph

I skimmed through this whole thread twice, but it seems you have a 98 chassis, if it was a rolling chassis at the time you got it, the gears possible could be different, you can figure out what gears you have by jacking up the rear of your truck, put it in neutral, spin one of the tires forward (spin it left if on drivers side rear, right if on passenger side rear) I'll type out the procedures as following..

1. Like I said before, jack up the rear of your truck by the rear axle, I don't like using the axle tubes, I prefer the diff case.

2. Crawl under the truck and mark a horizontal line about two inches long on the drive shaft with a piece of chalk, bright sharpie, or something.. when I say horizontal, I mean it should be parallel with the shaft itself, so draw the line on the shaft, and try to remember where it started, just spin the wheel until the line is facing right at you..

3. Now you can determine your gear ratio, which is the number of drive shaft revolutions that were made in relation to one tire revolution. For example, if your drive shaft rotated three and ~3/4 times in relation to one tire revolution, your gear ratio is 3.73s, if it rotated 4 and 1/10th times, then that's 4.10s, you probably half 3.42s or 3.73s.

So the gear ratio is the relation of your pinion gear to ring gear.

So in laymans terms, if someone had 3.42s and 265/75r16's, their gas mileage would be pretty good even for a TBI 350, but if that same person swapped out the 265s for 305/70R16s, and left the 3.42s, that would be hard on the truck and kill gas mileage, or if that person swapped out the 3.42s with 4.10s with 265s, those smaller tires would be spinning a lot more, and thus the truck would be a lot quicker off the line. But if you swapped out original 265s and 3.73s on my truck and put in 4.10s and 35s, it would compensate the larger tire for the lower gears, so gas mileage and speed would be about the same as stock, that's why people swap gears.

 

[1990GMCSIERRA]

dude u said u drive 80 miles a day,,**** 410 gears

 

[93Chevy_1500]

I didn't know you can drive 0 mph

I skimmed through this whole thread twice, but it seems you have a 98 chassis, if it was a rolling chassis at the time you got it, the gears possible could be different, you can figure out what gears you have by jacking up the rear of your truck, put it in neutral, spin one of the tires forward (spin it left if on drivers side rear, right if on passenger side rear) I'll type out the procedures as following..

1. Like I said before, jack up the rear of your truck by the rear axle, I don't like using the axle tubes, I prefer the diff case.

2. Crawl under the truck and mark a horizontal line about two inches long on the drive shaft with a piece of chalk, bright sharpie, or something.. when I say horizontal, I mean it should be parallel with the shaft itself, so draw the line on the shaft, and try to remember where it started, just spin the wheel until the line is facing right at you..

3. Now you can determine your gear ratio, which is the number of drive shaft revolutions that were made in relation to one tire revolution. For example, if your drive shaft rotated three and ~3/4 times in relation to one tire revolution, your gear ratio is 3.73s, if it rotated 4 and 1/10th times, then that's 4.10s, you probably half 3.42s or 3.73s.

So the gear ratio is the relation of your pinion gear to ring gear.

So in laymans terms, if someone had 3.42s and 265/75r16's, their gas mileage would be pretty good even for a TBI 350, but if that same person swapped out the 265s for 305/70R16s, and left the 3.42s, that would be hard on the truck and kill gas mileage, or if that person swapped out the 3.42s with 4.10s with 265s, those smaller tires would be spinning a lot more, and thus the truck would be a lot quicker off the line. But if you swapped out original 265s and 3.73s on my truck and put in 4.10s and 35s, it would compensate the larger tire for the lower gears, so gas mileage and speed would be about the same as stock, that's why people swap gears.

Thank you for that. That really helped. Im leaning towards the 3.73's more because Im not planning on running a bigger tire then a 265 for awhile. And I do think 4.10's would be a little much but figured I would throw it out there.

 

[RHamill]

Thank you for that. That really helped. Im leaning towards the 3.73's more because Im not planning on running a bigger tire then a 265 for awhile. And I do think 4.10's would be a little much but figured I would throw it out there.

Yeah no problem bud, 3.73s are a great gear for these trucks, because the most common lifts I'd say are 3" BL and simple leveling kits, and with them the most common larger tire people run is 33's and 35's, and with 3.73s - 33's will turn good with them, 35's not SO much but still not bad.

How bout a little rep?

 

[Swims350]

you got 5 spd. right if not then you got od? if so why worry about it, go 4.10's then you'll have alot of take off and low end grunt, and rpm's won't be bad with the od or 5th gear. Then if you do go bigger tires later it will be less of a dog and you'll be better off. If you ever do go bigger and you got 3.73's then it'll be worse of a dog depending on what size you go with, and you might be so unhappy with it you want to switch again.

 

[Sully]

Id run 4.10s on stocks....... you will get better mpg in town because your truck wont have to work as much.