Gears and Axle code

Justshootme84

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The top line "S807D" is termed the "Bill of Material" number. That's used for when you order parts, like axles or bearings, so they match your specific axle. Certain BOM's can also be used to ID the axle, such as the Ford 8.8". The bottom line is what you need to tell the gear ratio and axle type. It should read something like "3L55 8 8 9D12". The first number series in the tag is the gear ratio, and whether the axle has factory limited slip. In some cases, the first number of this series is covered up by the bolt holding the tag to the cover. That's why your's reads "L55 8 8 xxx". This is indeed the 3.55:1 gear ratio with the factory Trac-Lok limited slip. The next series is the axle type, that being the Ford 8.8" ring gear. The last series of numbers is the build date, which is Ford's code for the month and year the axle was built. JSM84

 

jsomedaysoon

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my door jamb sticker says that i have the 8.8 rear end with a factory limited slip. i did the trick where you lift the back wheels off the ground and the wheels spun oposite. if i remember correctly from an earlier post this means that i do NOT have a limited slip. so i tried to read the axle tag but it was rusted and covered with crap. i did the trick where you scrible a pencil on a piece of paper over it and this is what i got. tell me if it makes any sense. i think i got.... 8.8 or 8.6 (it is an 86 truck) 3 f 15 on a seperate line i see what apears to be a 388 if these numbers dont make any sense i'll try to clean it off better and read it again.

 

Justshootme84

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Try cleaning it again, you want to rad the bottom line of numbers starting from the bolt. You can also compare your gear ratio on the front axle ID tag. If your axle code is "H9", you should have 3.55 gears and factory limited slip in the Ford 8.8" rear axle. The front Dana44 TTB axle should be open with 3.54: 1 gear ratio. At least that's what your Bronco came with from the factory.

 
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jsomedaysoon

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Try cleaning it again, you want to rad the bottom line of numbers starting from the bolt. You can also compare your gear ratio on the front axle ID tag. If your axle code is "H9", you should have 3.55 gears and factory limited slip in the Ford 8.8" rear axle. The front Dana44 TTB axle should be open with 3.54: 1 gear ratio. At least that's what your Bronco came with from the factory.
okay i'll try this weekend. i do have the h9 axle code on the door jamb but i think i mentioned that the rear wheels spun oposite when i lifted the rear end off the ground. i'm just curious if i do have a limited slip or not. is it posible that the factory limited slip has not been taken care of and failed. would that cause the wheels to spin oposite? i'm not sure of the complete history of the truck but i do know tha not much on the truck is factory.

 

Justshootme84

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The surefire way to tell what you have is to remove the rear cover, and check if the gears and L/S have been replaced or not. The gear ratio should also be stamped into the ring gear, but I wasn't able to find it on my 88 Bronco when I gutted the 8.8" axle. If you have high mileage on the Bronco, it's certainly possible that the trac-lok is worn out and not working.

 

BLADE262US

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I agree with JSM on the worn limited slip . The clutchs wear very fast in tohose things and they will act just like an open diff doing the spin the wheel test . :D /emoticons/[email protected] 2x" width="20" height="20" />

 

Bronco_Willis

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Ok so here I am joining this thread. How can I tell what kind of front I have, if there is nothing readable on the door jamb? There is a tag on it but it read like this : 4 09 "upside down triangle" E7TA A. Thats the top line. Bottom line is this: "upside down triangle" 610267-6. Are these numbers irrelevant in figuring out my front end?

 

bigtimmer

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i have heard of welding the spidergears in the rear end together to make it a full positive traction

 

92bronco_in_progress

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Ok so here I am joining this thread. How can I tell what kind of front I have, if there is nothing readable on the door jamb? There is a tag on it but it read like this : 4 09 "upside down triangle" E7TA A. Thats the top line. Bottom line is this: "upside down triangle" 610267-6. Are these numbers irrelevant in figuring out my front end?

most broncos have a dana 44 up front.....axle ratio is the same as the rear.....so if you have 3.55 out back you have 3.55 up front, they have to match

 

Justshootme84

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Some have asked for pics to help ID the axle model. Here is the Ford 9" from my 84 Bronco. The rear cover is welded on, and the whole differential or 'chunk' comes out thru the front side or same side that the driveshaft goes in:

rear9.jpg


The metal ID tag is attached to one of the bolts:

rear9idtag.jpg


Here is the Ford 8.8" from my 88 Bronco. The rear cover is bolted on, and the ring gear+carrier comes out the back side/ opposite of the driveshaft. The ID tag is bolted on the back cover:

88bronco8.jpg


 
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jka7904

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Ok....I am trying to figure out the code that should be on my rear end. I'm thinking it should be S807D 3L55 8 8 ....but the tag is no longer on my rear end. Does this sound like a common code? Also, in the driver side door jamb, it has an H9. I know this stands for the limited slip option, which I know that my rear end is a limited slip with 3.55 gears and 8.8 so....can anyone help?

 

Justshootme84

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Ok....I am trying to figure out the code that should be on my rear end. I'm thinking it should be S807D 3L55 8 8 ....but the tag is no longer on my rear end. Does this sound like a common code? Also, in the driver side door jamb, it has an H9. I know this stands for the limited slip option, which I know that my rear end is a limited slip with 3.55 gears and 8.8 so....can anyone help?
You are correct. Might look on the front TTB axle pumpkin for the ID tag, should have a 3.54:1 gear ratio to match the 3.55:1 rear axle. JSM84

 

randyb

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ok Here is my axle code S838J (FIRST LINE) 3 55 88 5A27(SECOND LINE) NOW I AM ASSUMNG from what I have read that this is a 3.55:1 ratio 8.8 rear end, now there was no L in the number so does this mean there is no limited slip? also how do I identify if it is a DANA 44 ,70 or what?any help would be appreciated> thanks in advance

 

Justshootme84

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ok Here is my axle code S838J (FIRST LINE) 3 55 88 5A27(SECOND LINE) NOW I AM ASSUMNG from what I have read that this is a 3.55:1 ratio 8.8 rear end, now there was no L in the number so does this mean there is no limited slip? also how do I identify if it is a DANA 44 ,70 or what?any help would be appreciated> thanks in advance
You are correct, that is the tag numbers for a Ford 8.8" rear axle, with 3.55 gears and no limited slip or what's called an "open" differential.

 

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