this is the tag and numbers from a F150 STX (V831F / 3L55 /88/ 4D28 can any one helpme out withsize and ratio

 

Not sure of the size, but it is a 3.55 ratio, limited slip. (3L55 tells us that)

Does it look like the 8.8 illustrated here:

http://www.4wheelnoffroad.com/axle.html#Ford

 

yes it is the 8.8 ten bolt, I pulled the cover last night and found the gears in good shape, patern ware and depth was good but back lash is at .28 looks as though the front seal went out and they drove it till they could get to an oil supply,refilled but now have a growl. I suspect the pinion bearing will pull down and count teeth to be sure of ratio. owner said he had the ser.# check but his info is different from the diff. tag. this is an open end dif. not a L model. I will serch more.Vin 1FTR14W34NC08697