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12 Bolt 4.10's

Gear ratios

Gear ratios are the number of teeth on the ring gear divided by the number of teeth on the on the pinion. The circumfrence changes to allow more teeth that will stand up to the load onto the gear. If you doubled the teeth on any given ring gear without increasing the circumference, each tooth would be so thin, they'd break off the minute you put any kind of load on it.
 
Scroll down to the Q&A part.
http://64.233.167.104/search?q=cach...sletters/enl-09.pdf+dana+44+tooth+count&hl=en

I'm really tired of the misinformation allowed to run rampant on CK5.

Riddle me this, how big can a ring gear get before it's too big to fit in the hole in the case? You do realize that the change in size is done virtually all in the pinion gear, right? Like, the size of the ring gear might vary in the tenths of an inch. The easy way to indicate gear ratio is by counting teeth... you can also measure diameters.

For a set of "4.10s" you usually find either 45/11 for 4.09s, 41/10s for 4.10s, or 37/9s for 4.11s. It mostly depends on the diameter of the ring gear and the manufacturer as to which you'll find. While they can put any combination they want to on there some make more sense than others for the hypoid... due to noise and heat for example. Historically, the ones with the most teeth are the strongest (45/11).



EDIT:
PS: The fact that the pinion gear is the one to change sizes is why there are carrier breaks for most axles. If you were to use the same carrier for 2.73s and 4.56s then the 4.56s would have an obnoxiously thick ring gear... which is expensive to manufacture due to the volume of alloy required plus the difficulty of heat treating a large piece of metal like that without distortion or defects.
 
Just a thought, sometimes it's cheaper too do a axle swap instead of a gear swap. 3/4 ton axles can be found with 4.10 gears. Your call, just though I'd bring it up.
 
Diameters

To answer your riddle, I don't know how big it would have to be before it didn't fit in the hole. How big is the hole? Anything bigger than that measurement will not fit. What I DO know is that's why they make different size axles. If you could just make one size ring gear with any number of teeth on them, and they'd all be just as strong, then why would you have to replace your 10 bolts with Dana 60's or 14 bolts? If you have a 10 bolt and 12 bolt with different circumference gears, but the same tooth count, it still's the same ratio. It's not just a question of how big it is, it's how big it needs to be to handle the amount of torque going through it. The 1% rule may be an ok rule of thumb, it doesn't mean it HAS to be that way.
 
JFC.

You can't fit a 15" ring gear into a hole designed for a 8.875" ring gear. You do not change the size of a ring gear for a gear ratio. The size difference is ENTIRELY in the pinion gear. When tooth count changes so does the hypoid and so does the size of the teeth.

His question isn't about putting 5.13s in a 14FF vs 5.13s in a 7.2" IFS. It's about a 12 bolt. For a given axle, all gear ratios have the same diameter ring gear. The change is done entirely in the pinion gear. The tooth count just happens to follow the ratio in diameter between the ring gear and the pinion gear.

You can rattle on about different size ring gears in different axles and strength... but what does that have to do with his question? Are you trying to assert your intelligence by saying that a larger ring gear is stronger than a smaller one?

And quit harping on the different gear ratios thing. A tenth or even five tenths is not a big deal. If it was, GM wouldn't have done it. And Ford wouldn't have put 3.50s and 3.54s in their midsize vehicles. You can't seem to comprehend the simple fact that different rolling diameter tires far exceed the 1% or often the 2% difference. Think about it, a 31" tire only needs to have a rolling diameter 3/16" different than another tire to be at 1%.

I already explained to you why you have marginally different gear ratios. I'm actually kind of tired of talking about it because apparently you have a BS degree in ME and have designed thousands of gearsets.
 
A 12 bolt axle has a 8.875" diameter ring gear with it has a 2.43 ratio or a 4.56 ratio, just the teeth count change on the ring gear.
 
Alright, calm down Perfesser.

If you say so, tough guy. I stand behind what I said. I'm not saying your wrong or what you're saying is untrue, but niether is anything I've posted either. :bow: :surepal:
 
LongIslander26 said:
If you say so, tough guy. I stand behind what I said. I'm not saying your wrong or what you're saying is untrue, but niether is anything I've posted either. :bow: :surepal:
Click to expand...


Reeeaaaallly...

LongIslander26 said:
It's probably bigger on the 4.10's, which is why you need the new carrier to begin with, otherwise the teeth on the gear will be too thin. (There's more teeth on the gear). Call their tech line, they'll know. :D
Click to expand...

Nope, all the ring gears are the same size. The outside diameter varies a small amount.

The teeth on the ring gear don't get too thin. The ring gear gets too thick. I'd talk about thick, standard, and thin gearsets but that'd just confuse you. Maybe you should call the tech line so you'll know.

LongIslander26 said:
A (Very) rough guess would be somewhere in the neighborhood of 350 bucks. Remember you have to do the front as well! ;) :doah:
Click to expand...

He only asked about one axle, didn't he? I don't remember asking about two axles. It'll cost a little more than $400 for two decent gearsets. About $230 for one. What's this about calling a tech line? Yeap, that'd be my recommendation as well. :haha:

LongIslander26 said:
The slight difference in the gears front and rear will cause BIG problems if you run it in 4wd in anything other than mud or real loose ground. At any speed on even a firmly packed dirt road things will start to go "Boom" from the drivetrain being in constant tension. That's why they have to match front and rear with the same size tires.
Click to expand...

Nope, I've been telling you this for quite some time. I even gave you a link to read.

LongIslander26 said:
Gear ratios are the number of teeth on the ring gear divided by the number of teeth on the on the pinion. The circumfrence changes to allow more teeth that will stand up to the load onto the gear. If you doubled the teeth on any given ring gear without increasing the circumference, each tooth would be so thin, they'd break off the minute you put any kind of load on it.
Click to expand...

Nope again. The more teeth the merrier (within reason) for a given gear ratio. The circumference does not change on the ring gear. It changes on the PINION gear.
 
Gm Tsb

Well, here it is right from GENERAL MOTORS themselves.

http://service.gm.com:8083/forms/pdf/01-04-18-001A.pdf#search='Silverado%20Front%20differential%20noise'

I already said I AGREED WITH YOU, so how long are you going to beat this dead horse?
 
What am I supposed to get out of that TSB that I didn't already know?

Remember the "neither is anything I've posted either" post you just made? I was disproving your statement... which is what I've been doing ever since your very first post on this thread. I hate misinformation. All it does is screw people up.

I'm not beating a dead horse... I'm telling you that you're wrong and to quit spreading misinformation.
 
I personally have never run across a factory gearset with exact matching ratios

also, my old 79' k10 had a 10 bolt front with 3.40's i believe and the rear ratio i found out when i opened it up was 3.55's

which is way more difference then any factory spread i ever ran into and i never realized they were different till i had to change out the rear cause i blew up the Gov-Lok

also like cyber snyper said, even if you had matching ratios, the vehicle is still gonna gain driveline bind on high tractive surfaces because of things like tire pressures, tread height, and any small turns you may negotiate

WHICH IS WHY THE OWNERS MANUAL SAYS NOT TO RUN 4 WHEEL DRIVE LOCK/PART TIME ON ANY SURFACE IN WHICH THE TIRES CANNOT SLIP TO SOME DEGREE

also, this myth of the driveline exploding as soon as you hit pavement in 4wd is bunk, with that truck i mentioned that had a large difference between ratios i used to run from one trail to another that was close ON PAVEMENT in 4wd all the time
did it bind and sometimes hop-YES
did all my parts fallout on the road and i had to junk the truck then buy another-NO

the driveline is stronger then that, in fact its strong enough to force some slippage when the driveline binds up enough even on dry pavement
The nightmare problem would only arise if you did that to an excessive degree, or with huge tires in tight turns on light duty drivetrains (mine were 33's)
not that i'm telling you to do it either, cause it does cause a small amount of wear on things each time you do it, i'm just trying to give you real world examples


to answer the original question brother

tell the gear company you want 4.10's for a 12 bolt, they will send you what ever minor ratio change the sizes of the ring gear and pinion will allow (4.09, 4.10, 4.11, ETC...)to get a close enough match to your front 4.09's to make it work Be-a-utifully for you :waytogo:
 
i have a 77 with a dana 44 front (3.07) and a 12 bolt rear(3.73)
quite the bit of difference in gearing...... probly why i have a blown up front axle right now :D messed up my transfer case and dropped the drive shaft too. sucks for me just bought it.
 
I have owned and run Ford, Dodge, International and GM 4 WD vehicles. NONE of them had the exact same ratios front to rear, from the factory. Maybe my 70 K5 with the 12 bolt/44 does, but I have not checked.
 
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