Diameter of the ring gear?
difference of .01?

Be the ring gear 8" or 10' with the same tooth count nothing changes.
How do you split a tooth to get .01? I'm all ears.
Ratio of tooth count between ring and pinion unless you have a new angle on the laws of mechanics?

 

It has nothing to do w/ gear size, it also has nothing to do w/ "Plus there is no reason to worry about drive line bind on the road unless you're using 4x4" that comment, (which makes no sense at all), it is so when your going on tar, in 4X4, it goes smooth, if you don't believe me, call Ford Motor Company!

and no not EVERY truck EVER made came like that, but the majority of them did, not jsut ford, but any manufacturer.

and back to that comment about "Plus there is no reason to worry about drive line bind on the road unless you're using 4x4" your whole post makes no sense. they split the gears for using 4X4 on the road. many people will hit dry tar at SOME point in their truck's life in 4X4, and Ford knows this. That's why they split the gears, so that when these people w/ their brand new trucks hit the tar in 4X4, and it's kinda rough, they don't come back saying something is wrong w/ their truck. you must also remember, what about the old Full Time 4X4 trucks from back in the 70's and such.....there was no putting those trucks IN 2WD, so do they never use 4X4 on the tar?, or in bad conditions?, no they do it everytime they go down the road.

I know about the gear difference thing not by word of mouth, or some old guy told me, I know it stright from the MANUFACTURERS!

 

well see first you have to precision layout your ring gear and pinion gear. then you take a small yet poweful laser and very precisley proceed to cut through the middle of one of the teeth. then you go to the pinion gear and do the same thing on the mating tooth! that way you get .01"

DUUUUUUUUUUUUUUUUUHHHHHHHHHHHHHHHHHHH

-cutts-

 

well I remember it from a book I read like 5 months ago, and I finally found where in the book it was, so here it is, straight from the book,

"Although the difference between the ratios is small, the purpose is to prevent the driveline from binding. With the front differential ratio just slightly higher, the tendency is for the front of the vehicle to pull the vehicle thereby eliminating the problem of having the rear pushing at the same ratio as the front pulling. The different ratios also help reduce resonant vibration and noise created in the driveline."

All the information in this book is from engineers from Ford, GM, Chrystler, Honda, and Toyota mostly, and a few other stupid foreign companies.

Now I hope we can put this to rest....I hope

BTW, it is not always .01. That is just how Ford did it in their trucks, I have no clue what other manufacturers used for a difference

 

Thanks for backing me up.

My 2000 F150 has 3.73s front & rear.

Besides, if it had something to do with drivetrain binding, instead of the front binding, the rear would cause a bind as well.

and if you think the front should be pulling the rear, try running 3.27s in the front of your truck and 3.50s in the rear. Then go drive it in the snow/ice. You'll find it isn't a good idea either.

the point .01 difference can be made up with tire wear and air pressure.

 

then why did my '00 f150 have 3.55s front and rear if my comment makes no sense at all? I don't think my dive line exploded as i drove down the road.

Like everyone else has been trying to tell you, that .01 can be made up with tire pressures and wear, it really makes no difference and is not done on purpose.

 

Like I said, not all trucks had them, but many did. and that is the reason they did it. It may have been more of the older trucks that did, because their parts were more of a positive engagement, w/ all gear transfers, alxes w/ U-joints, instead of CV's. I really don't care if you guys don't believe me or not, it's your mistake not mine.

Like I said, call the manufacturer, and ask them

My bronco originally had matching 3.50 gears, w/ the 9", and D44, but the D44 I swapped into it that was leaf sprung out of a F-250, had 3.54.

Another truck I have has a 9" w/ 3.55 and a D44 w/ 3.54.....it's a '70.....like I said, I think it was an older truck kinda thing, like pre-80's

 

I've ran accross people that are under the impression that ring gears get bigger or smaller, with a ratio change. It comes from people using the terms "Taller" and "Shorter" when referring to gear ratios. It's taken up to half hour and practically had to pull a diff apart to explain it... I think he was still in disbelief at the end.

In short, for those that think ring gears somehow are smaller or larger diameter when you change the gear ratio, they're not. It's physically imposible to install smaller or larger ring gears into a diff they don't belong in. It's also impossible to use the pinion gear from a different gear ratio, because in order to change the ratio, the number of teeth on the pinion gear likely has to be different and/or gears come in matched sets and the sets must be used together.

 

Well it has nothing in the world to do with driveline "windup" sorry whoever wrote the book is on crack. Just like the guy that wrote the article in HR that said for the best 460 blocks find a D7TE, or D8TE truck block as they came from the factory with 4 bolt mains. Fact is those casting numbers were never used on 460s and non of the Truck blocks had 4 bolt mains from the factory, and the "truck" blocks didn't start until 1979, so just cause it's written don't make it so.
In this case the FACT is they did it cause thats what they happened to get from the gear manufacturer, not because it was a thought out anti windup engineering decision.
Let me give you some examples just on my own vehicles I have owned with factory gearing, 1969 F100 4.09 front, 4.10 rear, (D44, D60 combo factory) 1969 F100 D44 9" combo. 4.11frt 4.10 rear hmm guess they couldn't make up thier mind in 1969 which way to go. 1973 F150 D44/9" 3.54/3.50, 1974 F150 same axles 3.50/3.55 both factory, 1974 D44/*" 3.54/3.55. 1986 D44/8.8 3.08/3.10 1981 D44/9" 3.08/3.00 both factory gears. Your theory doesn't hold up cause they switch back and forth so that book was written just to make it sound like they were so smart and thought it out, and it just ain't so sorry.

 

again.. not so. A lot of the older trucks would match front and rear axles between manufacturers. ie: Dana front, ford rear.. Dana front chevy rear, Dana front and rear.

most newer trucks have axles matched with manufacture. My Ford has a Ford front and rear. Chevy's and Dodge's have AAM axles front and rear.

80s F250s had F3.54 / R3.54 gears until mid 85 because they ran Dana axles front and rear. I guess someone should have told Dana to make a 3.53 gear for the front axle, eh?

F250s after mid 85 had ford corporate rears (ie the Sterling 10.25") instead of a Dana 61 or 70 (which had 9.75" and 10.50" ring gears). Guess what, Sterlings had 3.55s instead of 3.54s.

Compare the ring gear size, gear ratio & teeth count between different axles and manufacturers.

FORD 8.8" RING & PINION
3.55 Ratio, 39-11 Teeth
3.73 Ratio, 41-11 Teeth
4.10 Ratio, 41-10 Teeth
4.56 Ratio, 41-9 Teeth

FORD 9" RING & PINION
3.50 Ratio, 35-10 Teeth
3.70 Ratio, 37-10 Teeth
3.89 Ratio, 35-9 Teeth
4.11 Ratio, 37-9 Teeth
4.56 Ratio, 41-9 Teeth
4.86 Ratio, 34-7 Teeth

FORD 9.75" RING & PINION
PART # TEETH RATIO
F975/308 OEM 40-13 3.08
F975/331 OEM 43-13 3.31
F975/355 OEM 39-11 3.55
F975/373 OEM 41-11 3.73
F97/410L * T/L 41-10 4.10
F97/456L * T/L 41-09 4.56

FORD 10.25" RING & PINION
E5TZ4209B 39-11 3.55
E5TZ4209C 41-11 3.73
E5TZ4209D 41-10 4.1
E5TZ4209F 41-09 4.56

DANA 44R 8.5" RING & PINION (reverse cut front)
28769-1X 42-12 3.50R
24638-1X 46-13 3.54R
24647-1X 41-11 3.73R
24649-1X 45-11 4.09R
D44/456R USG T/L 41-09 4.56R
D44/488R USG T/L 44-09 4.88R
D44/513R USG T/L 41-08 5.13R

DANA 70 10.50" RING & PINION
72168-5X 46-13 3.54
72154-5X 41-10 4.10
72152-5X 41-09 4.56
72148-5X 39-08 4.88
72156-5X 47-08 5.86