Limited slip differential - How can I tell

I have been changing oil in my '02 XLT, switching everything over to Amsoil, in my quest to get 22-24 MPG (I can't do 30 ALdive, I'm in the mountains).
I ordered the oil for the rear differential, but did not get the friction modifier. I didn't read far enough it seems. Anyway, how can I tell if I have the limited slip differential that is supposed to get the modifier.
I have an '02 XLT 4X4 with a howling rear end.

Dave

Never mind. The axle code on mine is D4 (found on the door pillar).
Using my handy dandy cd I downloaded, I find that D4 axle code is for the 3.73 ratio axle, which is limited slip. Crap, now I have to get some friction modifier.

Dave

talk with Aldive. Most synthetic fluids don't need friction modifier! mine didn't. Also..we have a chart on here with explorer specs and axle codes are under there.

-Drew

Drew,
Thanks for your reply. I have already ordered the modifier. Maybe it will just set on the shelf in the garage.

Where is the chart?

Dave

Here is the thread that Drew was referring to: http://www.explorerforum.com/ntrprize/Axle.htm. This is pretty interesting. I was wondering about the gear ratio on one of my vehicles, and I didn't know that the information is posted on the sticker on the door pillar. I'm always learning new stuff on this website, and helping other people out in the process. This is what is written on that thread:
Model Code Description Capacity Ratio
Bronco II 42 Regular 2640 3.45
44 Regular 2640 3.73
47 Regular 2500 4.10
D2 Limited Slip 2500 3.45
D4 Limited Slip 2640 3.73
D7 Limited Slip 2500 4.10
Ranger 72 Regular 2200 3.08
74 Regular 2200 3.45
82 Regular 2700 3.08
84 Regular 2700 3.45
85 Regular 2750 3.55
86 Regular 2700 3.73
87 Regular 2700 4.10
96 Regular 3200 3.73
F4 Limited Slip 2700 3.45
F5 Limited Slip 2750 3.55
F6 Limited Slip 2700 3.73
F7 Limited Slip 2700 4.10
K6 Limited Slip 3200 4.10
Explorer 43 Open 3200 3.08
41 Open 3200 3.27
42 Open 4.10
46 Open 3.73
45 Open 3200 3.55
D4 Limited Slip 3200 3.73
D2 Limited Slip 4.10
L73 Limited Slip 3.73

Thanks BB.

Dave

I have a 2002 Mazda B3000. Will the codes for the Ford Ranger apply for the type of rear
axel I have? If I understand the code on the driver side door sticker, it has Z under a R heading and 97 under the axel heading. I don't know what the Z is, but the Ranger code says it is a 4.10 ratio. The specs I looked up said it was a 3.73. I am lost..
thanks
glenn

I would add the modifier. I've also seen oils such as Royal Purple chatter without it.

For checking for a limited slip without a code, a good way to tell is to raise both rear tires in the air. Place the trans or transfer case in neutral. Rotate one tire. If the other tire turns the same direction, you have limited slip. If it turns the opposite direction, you either have an open diff, or a limited slip that is totally toast.

1995 explorer diff.

The code on the diff are:
6612b
3-55

Is this a limited slip w/ 355 gears???

Thx,
Jeff

Guys...you can't always depend on the codes. These vehicles are getting so old that many have had gear changes, complete housing changes, etc. If it's a 4X4, it is doubtful somebody changes BOTH sets...but it's possible. Check for posi as I mentioned above, and check the gear ratio by seeing how many turns of the driveline it takes to turn the wheels one turn. Or better yet, pull the cover and see first hand what gears are in it. It probably needs a lube change anyway.

I'm going into a LS pack rebuild next week, really late in the season... I may end up laying in some snow to pull this one off. I really need to get this one right the first time. So, I would like to explore a few topics:

1. I am buying the Ford Racing carbon rebuild kit from Summit. I will be getting 3 friction disks and 4 steels per side plus a shims, s-spring, and a cross-pin bolt. I have seen a couple of different layouts, does anyone have any informed suggestions on the order of frictions and steels?

2. I have 3 quarts of synthetic 75W140 waiting on the bench. It is Supertech brand, which is made by Warren for Walmart. I have a 4oz bottle of Ford friction modifier coming from Summit Racing with the rebuild kit. Like I said, I really want to get this right the first time. The general consensus appears to be to add 1/2 bottle, 2 oz, and drive to see for a few weeks checking for chatter. If so, add the rest. Is this a sound strategy? Can I add too much?

Any other words would be greatly appreciated. I will probably be on my back in less than 32 degree weather doing this, so I would really like to be able to go in, get it done right, and be done. Thoughts?

Me again... folks, I've posted nearly 1,000 times here trying to help people, and less than a dozen asking for help. I became an elite member within a week of joining the forum. I know many of you have done this job before me. I'm going to be on my back in below freezing weather later this week trying to accomplish this. If anyone has any special ideas, procedures, or simply an answer to the above questions, I could really use the help.

Thanks,

Phil

IF you have a helper, and a place to work, It may be easier to just pull the axle out, bring it into the house and do it there.

I've helped rebuild an 8.8 and rebuilt the dana 35 (TTB) and both time we just took them out of the truck (no choice on the TTB). It made life easier not having to lie under the truck.

Pulling the axle doesn't take long. Its just the e-brakes, drive shaft, shocks (lower mounts) and the u-bolts. Then 2 people can carry it.

~Mark

Personality flawed anti-social, I don't actually have any friends... LOL
I do, but I work a funky schedule and they work normal, so it's that way.

But, I know I can back it up to my shop door, and drag that bad thing inside. I never really considered it because everything under this Ex is stuck and rusty. I can see getting stopped on the driveshaft bolts for a couple of hours.

I'm more thinking tarps and space heaters at this point.

I somewhat answered my own first question because I only ordered one LS kit, so I only have 3 frictions per side, so therefore must use the stock sequence. I'm starting to understand shim selection, and I am not really looking for locker-class action, just want better snow/ice traction.

Unless someone gives me better words, I will use the synthetic lube and 1/2 bottle of friction modifier.

I'm whining. I love working on my explorer, I'm just on the fence... I would enjoy doing this work much more in the spring, and maybe I'll just live with no LS this winter. Thanks for the words.

Will it say thecode somewhere on the diff / axle because I don't have the original doors

Sticker isn't on the door, it's on the door pillar.(B pillar) Drivers side. Also there is a tag on the diff if someone hasn't removed it.

8-57b

old post i know. but i had a question about the axle codes. my 94 ranger regular cab 4.0 4x4 5 speed has the code D6 on the door pillar?
what is D6?
the tag on the axle says it is 3.73's and it IS a limited slip.