Swapping rear gears..Do I really need to swap the Front as well?

[87vertgt]

I only use four wheel drive when getting out of a parking space that is covered in snow.

I have 3:73 in front and want to get 4:10's in the rear. thanx

[GCncsuHD]

#1 YES!!!
#2 why would you want to go from 3.73 to 4.10s? you will barely notice a difference, definately not worth the money to swap

[Colby 04]

#1 YES!!!
#2 why would you want to go from 3.73 to 4.10s? you will barely notice a difference, definately not worth the money to swap


:iamwithst


don't use 4WD if you have different ratios installed
don't swap from 3.73 to 4.10, you will only notice that it sits about 100RPM higher at 70mph.

[Chuggs]

I can't really advise on the second part that these guys brought up, so I'll trust their posts. But the first part, I agree whole heartedly. You might hardly ever use it, but there will be that one chance you forget -- or worse yet, your significant other does. Save yourself the headaches and swap both.

[Monster Truck]

It would get ****ty traction if you had two different gear rations, and you would probably end up breaking something.

[1989K1500]

Dont regear only the back. The 4wd will be useless.

If you leave the front gears higher than the rear it would just spin the back tires faster then the front and make it squirley in the snow anyhow, plus if it gets traction front and rear it would put a lot of stress on the drivetrain.

[charsweb33]

If you want the 4:10 gearing, just put on shorter tires. However, I agree with the others that unless you are towing real heavy loads, the 4:10s will not do anything for you.

[Monster Truck]

Im regearing just my rear right now becuase I cant afford to do the front right this second and I just pulled the front drive shaft to ensure that it wont go into 4x4.

[TrmBrainInjury]

I did the same thing Monster, the rear in my truck grenaded the first time and I just had it fixed and went to a 4.10. I used it for a reason to lift the truck because when you lift it the front axle has to be taken down. When the front axle was loose I took it to get regeared and it cost a lot less because of the lack of labor needed to R&R it. Just make sure you keep that front driveline out until the front ratio matches the rear, you'll bind the t-case and explode it if you try to run two different ratios. J.T.

[Redz Z]

No one hit this point.

Transfer cases in our trucks are locked when engaged- there is no center differential; That means when it's engaged that it puts out power 50/50 to the front and rear. Now imagine a 3.73 front diff and a 4.10 rear diff and all 4 tires with even traction and then going forward or reverse. The rear differential is going to want to turn at a faster rotation then the front differential. The transfer case cannot slip to accomodate the faster rotation from the back and WILL be destroyed internally, because it is the only thing that has the ability to compensate for the different rotation speeds and it cannot do that.

And guys, a 4.10 on a set of stock 31s or 32s would make a pretty big difference. If the guy wants to keep stock height and tires, he cannot go any taller then a 4.10 anyways. Gears are usually to compensate for tire changes, but if the tires are left unchanged, gears alone can be a great way to get more torque to the tires faster. It allows the engine to get closer to peak torque at lower speeds. Better for towing for sure. Makes the engine more efficient at lower speeds and would probably give better in town mileage.

[TrmBrainInjury]

Just make sure you keep that front driveline out until the front ratio matches the rear, you'll bind the t-case and explode it if you try to run two different ratios. J.T.

I thought that was what I said?:think:

[Redz Z]

Ok you said the same thing in layman's terms.

[TrmBrainInjury]

lol, just tryin' to get my props yo. Not to mention I'm going blind trying to check out all those sweet trucks in your sig.

[h20son]

actually, when I swapped my 3.73's to 4.10's with 285's, I got back alot of power that I lost with the change from 265's to 285's


I can assure you that if you kick it in 4wd with those 2 gear ratios the transfer case does indeed make funny noises as the chain starts slipping

[Monster Truck]

I did the same thing Monster, the rear in my truck grenaded the first time and I just had it fixed and went to a 4.10. I used it for a reason to lift the truck because when you lift it the front axle has to be taken down. When the front axle was loose I took it to get regeared and it cost a lot less because of the lack of labor needed to R&R it. Just make sure you keep that front driveline out until the front ratio matches the rear, you'll bind the t-case and explode it if you try to run two different ratios. J.T.
How hard was it to pull the front axle? did you have to take absulutly everyting or just the cvs and acouplt bolts? I havent really looked at it.

[TrmBrainInjury]

I don't know why but I let a shop lift it, I don't think there's too much in the way. If you look under your truck you'll see the bolts that mount the axle, unhook the vent tube and electrical connection, and unbolt the cv's. I think it should come down pretty easy, the cv's collapse and move out of the way on mine but a stock truck might have to have the cv's taken out. I don't remember if there were brackets under the axle that had to come out or not.

[amurphree]

You have no reason to change gears, but if you did I would disconnect the front driveshaft and leave it out until you changed the front. The advanced by such a small change isn't worth not having 4wd.

[superx1965]

my 65 mustang had 3.00:1 gears and i changed them out for 3.25's even that made an unbelievable difference. Going from 373 to 410 will deff make a difference especially if ur truck is already geared too tall as a result of tire size etc.

[hillbilly2084]

i have read these post and kinda understand. But still have a few questions.

1. I have 3.42 gears with G80 code, 315's, 3" BL. I tow a 18' ski boat every weekend to the lake and back. Would yall recomend switches gears?

2. If so, what gears?

3. Should I swap to a 14 bolt rearend?

Also, I am on a very limited budget and the junk yards dont have anything right now.

Thanks...

[Redz Z]

Here are some answers for ya (at least my opinion)

1. Gears are for your preference, it cannot be decided in a one size fits all category. Do you have a manual tranny? Does your truck have a hard time getting going from a dead stop with/without the boat? Without the boat, is it (or are you) constantly going in and out of OD/5th on the highway? With the boat, are you constantly kicking down from D/4th to 2nd/3rd when you are pulling a hill?

Basically, if it isn't broke, don't fix it. If you are happy with it and it's performance, I wouldn't arbitrarily regear. It is a little harder on the drivetrain to get the 315's turning, but it's also hard on everything having the 315's bolted on in the first place.

2. If you decided that you wanted to regear, and this is my advice to ANYONE that want's to upgrade to a 4.10 or 3.73- I would keep an eye out for a 4.10/3.73 front/rear axle setup from a junked IFS truck. You should be able to get both axles for $500 and it is a simple bolt in operation. This is going to be much cheaper then a $1200+ gear install and you know it will be setup right.

3. This would tie into #2- If you decide to regear and find a junked IFS truck with the 14 bolt SF rear (any 3/4 ton 6 lug truck) then take it. The 14 bolt SF is a much stronger axle. However, I would just drive your current setup until you had problems. MOST guys only have problems when they are running oversize tires and do brake stands and/or hard offroading. For regular driving and towing you are probably ok.

[hillbilly2084]

Thank for the help. I have an auto tranny, it is kinda hard to get going from a stop but not to bad imo. I usually dont drop down gears on the highway. Towing the boat though puts a good strain on the truck. Would regearing help on my mpg? I am gettting approx. 10mpg right now after a full tune up. Thanks again.

[Loki]

you want to change them both...the front and rear output shaft on your tcase will end up spinning at differant rpms and you'll end up tearing something up in the box. 4.56's would be a nice jump from the stock 3.73s

[Redz Z]

Thank for the help. I have an auto tranny, it is kinda hard to get going from a stop but not to bad imo. I usually dont drop down gears on the highway. Towing the boat though puts a good strain on the truck. Would regearing help on my mpg? I am gettting approx. 10mpg right now after a full tune up. Thanks again.

Hmmmm... Since you tow, your mileage is pretty poor, and your starts from a stop are pretty hard, I think you would be a good candidate for a regear. that mileage is pretty horrible for a tuned Vortec 5.7L with 35s. You should at least be 12-14mpg.

This would be my advice-

1. Keep an eye open for a junked IFS truck, 1/2 or 3/4 ton 6 lug with 4.10s. You should be able to find one; Especially since so many guys are now doing solid axle swaps and their IFS stuff just sits there, it shouldn't be that hard. I would imagine you could buy the front and rear axles complete rotor to rotor for not a penny more then $500. You could bolt it all in within a weekend. I would give it a 3/5 wrenches in terms of difficulty. It would also be a good time to think about a suspension lift if you are considering it, since it will be a lot of redundant work to change the axles out.

2. Regear your current axles with aftermarket gears to 4.56s. This would be anywhere from $1000-$1200 installed. A 4.56 wasn't a factory option but it would probably be the best for you. It will be more expensive though then a self performed axle swapout.

So, it's a 4.10 with a cheaper overall cost but more work for you, or 4.56 with new gears installed at a higher cost. Either one will give you better results in terms of towing, mileage and drivability.

Keep in mind that in going from 10 to 12 MPG, it is going to take you a LOT of miles to payback the cost of gears at a payoff of a few cents per mile.