This may sound strange, but I'm starting to wonder if my 2002 Fx4 with the 4.6 & automatic actually arrived with the 3.55 limited slip rear end I ordered. This rear end looks quite a bit different than my '97 with LS. (It also looks different than my '99, but that had the 5.4 and thus had the bigger rear end.) Since we all know that the 4.6 can't spin the tires (to see if they both spin) unless you're on KY jelly or something similar, are there any external differences I can look for?

 

Get yesterdays newspaper.
Place the sports section under the left rear.
Place the local section under the right rear.
Stomp.
Examine results.

 

Jack up the rear end so both wheels are off the ground. Spin one of the wheels. If they both turn in the same direction, you've got the LS. If they spin in opposite, it's open.

 

Also there should be a tag on either side of diff cover, saying 3 LS 55 which means limited slip....thats what was on mine any way, also it will say somewhere on there the ring gear size.

 

There is no external differences between the LS and non LS. The only way to tell is to look at the tag on the diff housing, look at the vin, look at the door sticker, or take off the diff cover to look inside.

 

You're (all) right. I jacked it up, put it in Neutral and both tires spin in the same direction. I also checked the tag and it says LS. Many thanks. Now if that puppy little 4.6 could only spin them!

By the way, I tried the newspaper trick, but only one side spun. I then checked the paper and found it to be full of political adds from before election day. Of course it was slicker than the Sports section under the other side!