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Old Dec 11, 2008 | 01:07 PM
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Gear Ratio

How can I tell what Gear ratio my truck has? I'm sure there is a service code/tag somewhere, just gotta find it HAHA.

I know at 70 MPH, in OD, my truck runs about 2100-2200 RPM's
 
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Old Dec 11, 2008 | 01:47 PM
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Look on your door sticker, it will say Axle and then a 2 digit number. Then post it here and we will tell you. Most likely you have H9, which is a 3.55 LS.
 
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Old Dec 11, 2008 | 01:52 PM
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Mine says 19 under where it says axle
 
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Old Dec 11, 2008 | 02:44 PM
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3.55 not limited slip.
 
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Old Dec 11, 2008 | 08:22 PM
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Ron, might i ask if you are familiar w/limited slip, to the point of knowingn what holds the clutch packs "tight" on ea. side. Is it just the big pin thats locked into postion with the bolt? I've read may posts where these clutch packs were factory installed too tight, causing shudder when turning curves. The reason i ask is i have just purchased a low mileage 9.75 to replace my 8.8 in a 05 scab, 4.6. Before i swap out, i had thought about inspecting/maybe replacing these clutches, but when i remove that big pin, will the side gears spring inward (after removing c clip), and have to be compressed upon re-assy? Or is it just a manufacturing tolerance build up, causing possible uneven "compression" per side? I saw you worked at Ford for several yrs. I should prob. start a new thread. thanks for any help....paul
 
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Old Dec 11, 2008 | 08:33 PM
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To replace the clutches on a 9.75 you need the ford tool. There is no other way to do it unless you somehow made your own tool.

As far as the chattering goes, just drain the fluid and install new gear oil and friction modifier.
 
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Old Dec 11, 2008 | 08:56 PM
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thanks,,,,i've seen exploded veiws of the axle, and no springs in there, so i guess there just compressed in very tight at the factory, so this special tool 1) holds the side gears in place while your removing the c-clips, and 2) has a tension adjustment so you can slowy adj. the tool whichever way, to release the side gears, then you can remove all the parts? I also wanted to check the race on the axle shafts also, but maynot be able to now. BTW,,,i thought this bigger axle hsg assy would have larger outer bearings, since its a 34 spline. But i did some research on the seal and brgs for these, and there the same as 8.8, as far as i could tell by p/n's and such. So how can a larger axle (34 splines) vs 31, on 8.8, be the same diameter? Looks like only the carrier is the "heavy duty" part. thanks....paul
 
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Old Dec 12, 2008 | 08:44 AM
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They do have a spring.. but not the conventional spring you are thinking of. It looks like a normal shim, but it has a slight inward curve to it, which makes it work like a spring.

The ford tool pushes the 2 side gears outward to relieve tension on the other spider gears. Which allows you to turn the carrier and remove the 2 spider gears. Kinda hard to explain, but if you seen someone rebuild one you would know what I talking about.

The 9.75 and 8.8 don't use the same bearings, the 9.75 the bearing are bigger.
 
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Old Dec 13, 2008 | 06:02 PM
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is the 19 not limited slip meaning like a''posi'' so that both tires spin all the time? Mine is 19 and usually 1 tire spins when i can get it too
 
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Old Dec 13, 2008 | 06:30 PM
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mine says RC-11
 
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Old Dec 14, 2008 | 05:59 AM
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If the AXLE code begins with a letter, it has Limited Slip.

If the AXLE code begins with a number, no Limited Slip.

billnuke1: Where are you looking? Above or below the AXLE code on the Certification Label?

There's no such thing as an AXLE code of RC-11; RC; or 11.

There are some AXLE codes that begin with an R, followed by a number, but they all are listed for Rangers, not Excursions.
 
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Old Dec 14, 2008 | 08:21 AM
  #12  
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Paul, what year truck did your 9.75" come from? If your going to use it to replace the one in your 05, than the 9.75" would have had to have come from a 04(new body style) or newer, due to the shock mounts are outbound.
Rich
 
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Old Dec 14, 2008 | 01:45 PM
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The code is above. I have taken a picture but I'm not allowed to do attachments yet.
 
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Old Dec 20, 2008 | 05:29 PM
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I have a 9.75 in my 03 screw. Ls 3.73 gear ratio.

I am putting a new axle seal on and had to have the right size since both the 8.8 and 9.75 are listed as options for that year.
 
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Old Dec 20, 2008 | 07:31 PM
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Originally Posted by fordcoolmandude
I have a 9.75 in my 03 screw. Ls 3.73 gear ratio.

I am putting a new axle seal on and had to have the right size since both the 8.8 and 9.75 are listed as options for that year.
The 4.2 and 4.6 get the 8.8, and the 5.4 gets the 9.75.
 
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