trying to find out what rear end i have . tag # is SL 55 88 8A26 0ther # is 58690 r:o

 

Look on the door jamb sticker. It'll say: "Axle: ##"

 

There should be a tag on the drivers door jamb that has a 2 digit axle code. Get that and check the axle list.

 

Axle Codes (LS=Limited Slip / Traction Lok):

F-150:
19 – 3.55 Non-LS
18 – 3.08 Non-LS
H9 – 3.55 LS
B6 – 3.73 LS

F-250:
27 – 3.31 Non-LS
26 – 3.73 Non-LS

Ranger:
84 – 3.45 Non-LS
86 – 3.73 Non-LS
87 – 4.10 Non-LS
89 – 4.56 Non-LS
F6 – 3.73 LS
F7 – 4.10 LS
92 – 3.08 Non-LS
R5 – 3.55 LS
91 – 3.27 Non-LS
96 – 3.73 Non-LS
R6 – 3.73 LS

 

That's an 8.8" 3.55 limited slip.

L55 and 88 - see the pattern?

 

Yep. I figured it was a 3.55 but did not pick up on the LS or the 8.8