Differentials, 4.09 front, 4.10 rear

On Mon, 19 Mar 2007 19:23:49 -0500, "Tom" <tjctransport.TakeThisOut@optonline.net>
wrote:

>it is normal to have the differential gears 1 point off. this makes the
>front turn a tad faster than the rear, which aids in the fronts pulling
>power.


It is not a bad idea to have it that way but sometimes it is because
the series of axles that they are using only come that way. It used to
be pretty common long ago but you do not see it that way today on new
vehicle much at all anymore.
-----------------
TheSnoMan.com
 >> Stay informed about: Differentials, 4.09 front, 4.10 rear 

me at <my.address RemoveThis @is.invalid> wrote:
>
>Have had some more trouble finding parts. Is it true that it is
>ok to run 4.09 in front with 4.10 in the rear?

Okay, imagine what happens with a four-wheel drive system where the
front wheels are turning at a different speed than the rear wheels
when you're going straight down the road.

Not a good idea.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."
 >> Stay informed about: Differentials, 4.09 front, 4.10 rear 

In article <etnbu6$f4i$1@panix2.panix.com>,
kludge RemoveThis @panix.com (Scott Dorsey) wrote:

> me at <my.address RemoveThis @is.invalid> wrote:
> >
> >Have had some more trouble finding parts. Is it true that it is
> >ok to run 4.09 in front with 4.10 in the rear?
>
> Okay, imagine what happens with a four-wheel drive system where the
> front wheels are turning at a different speed than the rear wheels
> when you're going straight down the road.
>
> Not a good idea.
> --scott

From the Randy's Ring and Pinion web site;
Myths about differentials
"The gear ratio in the front of a four wheel drive has to be
different from the front so the front wheels will pull more."
---------------------------------------
"There have been many different ratio combinations used in
four-wheel drive vehicles, but not so that the front will pull
more. Gear manufactures use different ratios for many different
reasons. Some of those reasons are: strength, gear life, noise
(or lack of it), geometric constraints, or simply because of the
tooling they have available. I have seen Ford use a 3.50 ratio in
the rear with a 3.54 in the front, or a 4.11 in the rear with a
4.09 in the front. As long as the front and rear ratios are
within 1%, the vehicle works just fine on the road, and can even
be as different as 2% for off-road use with no side effects."
 >> Stay informed about: Differentials, 4.09 front, 4.10 rear 

On 19 Mar 2007 21:04:06 -0400, kludge DeleteThis @panix.com (Scott Dorsey) wrote:

>Okay, imagine what happens with a four-wheel drive system where the
>front wheels are turning at a different speed than the rear wheels
>when you're going straight down the road.


Actually this happens all the time and this is why you do not use
convential 4x4 on pavement. It happens because of minor differences in
tire rolling radiuses due to inflation and load and when ever you turn
because the front and rear axle have different rolling paths in a
turn. Also, the ujoints in a solid front axle that allow you to steer
the axle under power are not constant veleocity and the sharper you
turn, the more the speed across the joint varies as it flexs (this is
why the wheel can whip and bind in a tight turn with a solid front
axle on a hard tractive surface.
-----------------
TheSnoMan.com
 >> Stay informed about: Differentials, 4.09 front, 4.10 rear 

Scott Dorsey wrote:

> me at <my.address.RemoveThis@is.invalid> wrote:
>
>>Have had some more trouble finding parts. Is it true that it is
>>ok to run 4.09 in front with 4.10 in the rear?
>
>
> Okay, imagine what happens with a four-wheel drive system where the
> front wheels are turning at a different speed than the rear wheels
> when you're going straight down the road.
>

That's what 2WD mode is for
 >> Stay informed about: Differentials, 4.09 front, 4.10 rear 

Scott Dorsey <kludge.TakeThisOut@panix.com> wrote in article
<etnbu6$f4i$1@panix2.panix.com>...
> me at <my.address.TakeThisOut@is.invalid> wrote:
> >
> >Have had some more trouble finding parts. Is it true that it is
> >ok to run 4.09 in front with 4.10 in the rear?
>
> Okay, imagine what happens with a four-wheel drive system where the
> front wheels are turning at a different speed than the rear wheels
> when you're going straight down the road.
>
> Not a good idea.


Perhaps the engineers at the "Big Three" manufacturers need to be told
this, because they all intentionally engineer a point or two difference.

What do YOU know that THEY don't?

And. why are you working at that mundane job when you SHOULD be designing
cars?
 >> Stay informed about: Differentials, 4.09 front, 4.10 rear 

On Tue, 20 Mar 2007 12:14:38 -0500, "*" <nospam.RemoveThis@this.addy.com> wrote:

>Perhaps the engineers at the "Big Three" manufacturers need to be told
>this, because they all intentionally engineer a point or two difference.


No they do not today because I have a 79, a 89 and a 2000 that all
have the EXACT same gear ratio front and rear. BTW, Detriot knew about
the bind many years ago and promotted fulltime 4x4 with a differentail
between front and rear axle (I have one still) from 1973 till 1979
until fuel cruch killed them off as they were more thirsty. It was a
very slick setup though speaking from first hand use of one for over
20 years now.
-----------------
TheSnoMan.com
 >> Stay informed about: Differentials, 4.09 front, 4.10 rear 

On 19 Mar 2007 21:04:06 -0400, kludge DeleteThis @panix.com (Scott Dorsey) wrote:

>me at <my.address DeleteThis @is.invalid> wrote:
>>
>>Have had some more trouble finding parts. Is it true that it is
>>ok to run 4.09 in front with 4.10 in the rear?
>
>Okay, imagine what happens with a four-wheel drive system where the
>front wheels are turning at a different speed than the rear wheels
>when you're going straight down the road.
>
>Not a good idea.
>--scott

Not enough difference to matter. Tire pressure differences would have
the same effect as would changes in load.
1/100 is not enough to make a difference you will ever sense from the
driver's seat.
-
Regards
Gordie
 >> Stay informed about: Differentials, 4.09 front, 4.10 rear 

> BTW, Detriot knew about
> the bind many years ago and promotted fulltime 4x4 with a differentail
> between front and rear axle (I have one still)
> TheSnoMan.com

How does that work for you off-road or on loose surfaces? I would guess
that a differential between the front and rear would lead to a greater
likelyhood of getting stuck because both wheels on one axle lost traction
and one wheel on the other axle lost traction at the same time. I have
heared of some vehicles (newer Jeeps for instance) in which you can drive in
"all-wheel-drive" mode (i.e. center diff), then lock the center diff for 4x4
mode.
 >> Stay informed about: Differentials, 4.09 front, 4.10 rear 

The Nolalu Barn Owl <&#103&#111&#114&#100&#105&#101&#64&#110&#111&#108&#97&#108&#117&#46&#111&#110&#46&#99&#97> wrote:
>
>Not enough difference to matter. Tire pressure differences would have
>the same effect as would changes in load.

Yup, that's true.

>1/100 is not enough to make a difference you will ever sense from the
>driver's seat.

Is it enough to seriously impact tire wear, though?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
 >> Stay informed about: Differentials, 4.09 front, 4.10 rear 

Sounds like a bunch of hooey to me.


"Tom" <tjctransport.RemoveThis@optonline.net> wrote in message
news:0YELh.935$mg7.686@newsfe12.lga...
> it is normal to have the differential gears 1 point off. this makes the
> front turn a tad faster than the rear, which aids in the fronts pulling
> power.
> "me at" <my.address.RemoveThis@is.invalid> wrote in message
> news:45ff0536$0$14058$742ec2ed@news.sonic.net...
>>
>> Have had some more trouble finding parts. Is it true that it is
>> ok to run 4.09 in front with 4.10 in the rear?
>>
>> Thanks,
>>
>> Vic
>>
>>
>> -----------------------------------------------------------------
>>
>> 1971 Chevrolet K20
>> 3/4 Ton
>> Long Bed Fleetside
>> 4WD
>> 350
>> 4 on the floor
>> Transmission - Muncie 465 - 6.55:1 3.58:1 1.70:1 1.00:1
>> Transfer case - New Process 205 - 1.98:1 1.00:1
>> Warn manual hubs
>> Front Diff - Dana 44 - Open - 4.09:1
>> Rear Diff - Eaton H070 - Detroit Locker - 4.10:1
>> (Should be a
>> (H052 for 3/4-ton,
>> (H072 for 1-ton.
>> (current H070 is a 1-ton from a 1965)
>>
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 >> Stay informed about: Differentials, 4.09 front, 4.10 rear 

me at wrote:
> Have had some more trouble finding parts. Is it true that it is
> ok to run 4.09 in front with 4.10 in the rear?
>
> Thanks,
>
> Vic
>
>
> -----------------------------------------------------------------
>
> 1971 Chevrolet K20
> 3/4 Ton
> Long Bed Fleetside
> 4WD
> 350
> 4 on the floor
> Transmission - Muncie 465 - 6.55:1 3.58:1 1.70:1 1.00:1
> Transfer case - New Process 205 - 1.98:1 1.00:1
> Warn manual hubs
> Front Diff - Dana 44 - Open - 4.09:1
> Rear Diff - Eaton H070 - Detroit Locker - 4.10:1
> (Should be a
> (H052 for 3/4-ton,
> (H072 for 1-ton.
> (current H070 is a 1-ton from a 1965)
>
>
>
>

I was always under the impression that you never use 4WD on hard
pavement and that was the reason. This was told to me back in the 70's...
 >> Stay informed about: Differentials, 4.09 front, 4.10 rear 

SilverStude wrote:
> me at wrote:
>> Have had some more trouble finding parts. Is it true that it is
>> ok to run 4.09 in front with 4.10 in the rear?
>>
>> Thanks,
>>
>> Vic
>>
>>
>> -----------------------------------------------------------------
>>
>> 1971 Chevrolet K20
>> 3/4 Ton
>> Long Bed Fleetside
>> 4WD
>> 350
>> 4 on the floor
>> Transmission - Muncie 465 - 6.55:1 3.58:1 1.70:1 1.00:1
>> Transfer case - New Process 205 - 1.98:1 1.00:1
>> Warn manual hubs
>> Front Diff - Dana 44 - Open - 4.09:1
>> Rear Diff - Eaton H070 - Detroit Locker - 4.10:1
>> (Should be a
>> (H052 for 3/4-ton,
>> (H072 for 1-ton.
>> (current H070 is a 1-ton from a 1965)
>>
>>
>>
>>
>
> I was always under the impression that you never use 4WD on hard
> pavement and that was the reason. This was told to me back in the 70's...
test
 >> Stay informed about: Differentials, 4.09 front, 4.10 rear