decoding the rear end tag.
 

Can some one tell me what all the numbers on my rear end tag mean. Is it useful information of is it just a part number?

Top line is S847F (the S may be a 5)
Bottom line is 3L55 88 4021

This sounds like a job for NumberDummy!

I've been searching some since I posted this. It looks like the 3L55 stands for a 3:55 gear with a limited slip differential.

I'm guessing that the 88 stand for a 8.8in rear end. Mine is a 10 bolt.

Yep its a 3.55 LS

Thanks Lew52.

what does the S847F and 4021 stand for?

The info in this thread might help decipher what the other alphanumerics are: Ford Ranger Rear Axles - The Ranger Station

One is a build date and I forget what the other one is. You've already got the most important pieces of information off the tag.

GM guy in this thread :)

:-X24 i thought the exact same thing!

The S847F says it was made at the S=Sterling Plant and the 847F is the application code for the type of Ford it was used on and how much the axle can hold.

It is also a 3.55:1 ratio limited slip 8.8" rear end.

Your date code is not right at it says it was made on the 21st day of the 14th month of 1994.

Tag decoding :

3L55 88 99H06

Second part is the axle ratio: There should be a "3L" preceding the 55 if it's a Limited Slip. If it's open, it would just say '355' .
4th is the ring gear diameter, in your case an 8.8 inch.
5,6,and 7 are the build year, month, and day, in this case, August 6th, of '99. (9=1999, H=8th month [and there is no 'I' in the sequence]) and '06' is the 6th.

http://i54.photobucket.com/albums/g9...nd/AxleTag.jpg

/

Awesome thanks.

It's not really acting like a limited slip rear. I guess I need to change the rearend fluid and conditioner. On the other hand it would explain why it wont burn the tires when I punch it.

The clutch packs are known to wear out. You can get replacements from many online vendors. For a few $$ more you can upgrade to the kevlar model. A simple fluid change is probably not going to fix your problem.

I was wondering the same thing, cool to know I have a limited slip and not open.:)

I thought it was just low on power, but since my truck's been at the tranny shop this week and I'm driving my dads '00 Jimmy, that makes my truck feel like a sports car!

how about decoding this tag
WCD-E
300 4MD 403

WCD-E:
1965 Thunderbird
3.00 Ratio
39 teeth R.G.
13 teeth P.
9.0 Dia of R.G.
NL
28 Axle shaft splines.

Thank you very much