Changing axle ratio
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Changing axle ratio
Right now my truck has 4.10 geared axles. I was wondering if you can just change the gears inside the axle to make it more suitable for highway speeds with out getting whole different axles? I'd like to be able to do 65-70 at around 2000-2500RPM.
It is a 4wd but I've only used 4wd twice since I bought it a year ago so its not like I need the gears I have right now to go off roading or towing or anything like that.
It is a 4wd but I've only used 4wd twice since I bought it a year ago so its not like I need the gears I have right now to go off roading or towing or anything like that.
Post Fiend
Joined: Mar 2005
Posts: 8,542
Likes: 5
From: Louisiana
4.10s are definatly too low of a gear for hwy speeds with only 1:1 final gears, but they definatly are great for in town use to get that big/heavy truck moving.
IF you change the rear gears, you have to change the front or if you put the truck in 4wd, the transfer case will bind and you'll hear one big,expensive bang!
Changing gears is nothing for a avearge DIY mechanic. I know how, seen how, understand how, but still didn't feel comfortable enough to do it myself, so I brought it to a professional.
You're looking at about $600 and axle for parts(ring and pinion, master install kit) + tax, and labor, and that's if you don't install any traction aids(LS, Locker).
You'd need something around 3.00 gears to get that low of an RPM at hwy speeds, but the acceleration is going to suck!
You will get terrable gas mileage trying to accelerate, b/c the engine will be straining to get the heavy truck moving(b/c it doesn't have enough gear).
Depending on your tire size, you might have enough room to install larger tires to affectively lower(numatically) your gear ratio, which would be easier/cheaper than changing gears front and rear and lower your hwy RPMs at the same time.
IF you change the rear gears, you have to change the front or if you put the truck in 4wd, the transfer case will bind and you'll hear one big,expensive bang!
Changing gears is nothing for a avearge DIY mechanic. I know how, seen how, understand how, but still didn't feel comfortable enough to do it myself, so I brought it to a professional.
You're looking at about $600 and axle for parts(ring and pinion, master install kit) + tax, and labor, and that's if you don't install any traction aids(LS, Locker).
You'd need something around 3.00 gears to get that low of an RPM at hwy speeds, but the acceleration is going to suck!
You will get terrable gas mileage trying to accelerate, b/c the engine will be straining to get the heavy truck moving(b/c it doesn't have enough gear).
Depending on your tire size, you might have enough room to install larger tires to affectively lower(numatically) your gear ratio, which would be easier/cheaper than changing gears front and rear and lower your hwy RPMs at the same time.
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I just looked in your gallery and assumed that was the truck you wanted to swap gears in...I also assumed those were 33's. If that is the case I just plugged and played with some numbers in one of the calculators. With a 3.73 gearing you'll be at 2658 rpm. With around a 3.50 gearing you'll be at right around 2450 rpm. Hope this helps
The tires are 9.5-16.5.
Thread Starter
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Senior User
Joined: Jul 2007
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4.10s are definatly too low of a gear for hwy speeds with only 1:1 final gears, but they definatly are great for in town use to get that big/heavy truck moving.
IF you change the rear gears, you have to change the front or if you put the truck in 4wd, the transfer case will bind and you'll hear one big,expensive bang!
Changing gears is nothing for a avearge DIY mechanic. I know how, seen how, understand how, but still didn't feel comfortable enough to do it myself, so I brought it to a professional.
You're looking at about $600 and axle for parts(ring and pinion, master install kit) + tax, and labor, and that's if you don't install any traction aids(LS, Locker).
You'd need something around 3.00 gears to get that low of an RPM at hwy speeds, but the acceleration is going to suck!
You will get terrable gas mileage trying to accelerate, b/c the engine will be straining to get the heavy truck moving(b/c it doesn't have enough gear).
Depending on your tire size, you might have enough room to install larger tires to affectively lower(numatically) your gear ratio, which would be easier/cheaper than changing gears front and rear and lower your hwy RPMs at the same time.
IF you change the rear gears, you have to change the front or if you put the truck in 4wd, the transfer case will bind and you'll hear one big,expensive bang!
Changing gears is nothing for a avearge DIY mechanic. I know how, seen how, understand how, but still didn't feel comfortable enough to do it myself, so I brought it to a professional.
You're looking at about $600 and axle for parts(ring and pinion, master install kit) + tax, and labor, and that's if you don't install any traction aids(LS, Locker).
You'd need something around 3.00 gears to get that low of an RPM at hwy speeds, but the acceleration is going to suck!
You will get terrable gas mileage trying to accelerate, b/c the engine will be straining to get the heavy truck moving(b/c it doesn't have enough gear).
Depending on your tire size, you might have enough room to install larger tires to affectively lower(numatically) your gear ratio, which would be easier/cheaper than changing gears front and rear and lower your hwy RPMs at the same time.
Right now first gear is so low that I always use 2nd gear to start out on even on hills.
I just put the axle back together for my Camaro so this is something I can do myself.
Post Fiend
Joined: Mar 2005
Posts: 8,542
Likes: 5
From: Louisiana
Do you have the proper tools to check the backlash and a press for the bearing on the pinion?
The granny low first gear will help get the truck moving if you have 3.00 gears, but after that, your truck will be pretty slugish.
The granny low first gear will help get the truck moving if you have 3.00 gears, but after that, your truck will be pretty slugish.
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Post Fiend
Joined: Mar 2005
Posts: 8,542
Likes: 5
From: Louisiana
Yukon gears, randy's ring and pinion....
Somewhere around 3.25 would be better for hwy driving, but if you tow or do a lot of in town driving, it's not worth it.
Timken bearings are real good, but a master install kit from yukon or somewhere else would be good enough.
It'll be about $150 for each ring and pinion and about $90 each master install kit plus gear oil and new gaskets or RTV
$500 in parts alone plus tax or shipping.
And that's assuming you set everything up right and not start chipping teeth off the ring gear the first time you use it, then needed to buy everything all over again and have a professional do it.
Somewhere around 3.25 would be better for hwy driving, but if you tow or do a lot of in town driving, it's not worth it.
Timken bearings are real good, but a master install kit from yukon or somewhere else would be good enough.
It'll be about $150 for each ring and pinion and about $90 each master install kit plus gear oil and new gaskets or RTV
$500 in parts alone plus tax or shipping.
And that's assuming you set everything up right and not start chipping teeth off the ring gear the first time you use it, then needed to buy everything all over again and have a professional do it.
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From: southeren Oh
Here is the formula for figuring the RPM at any speed. This works for RPM in 4th gear in a 5sp (NOT in overdrive)
MPH X Gear ratio X 336 divided by Overall Tire height in inches = RPM
Examples :
60 X 3.50 x 336 / 31 inch tire = 2276 RPM
60 X 4.11 x 336/ 31 inch tire = 2672 RPM
MPH X Gear ratio X 336 divided by Overall Tire height in inches = RPM
Examples :
60 X 3.50 x 336 / 31 inch tire = 2276 RPM
60 X 4.11 x 336/ 31 inch tire = 2672 RPM