Has anyone had any luck replacing the stock rear axle from a 97-03 F150 with one from a Mustang. I don't know much about the Mustang's, but I'm sure they're POSI-Trac, right? Right now only one of my tires spins when I burn out, and that just won't do when I take it to test & tune night @ the drag strip.

 

You can get a lsd or locker set up for your axle. No need to take one out of a Mustang.

http://www.currieenterprises.com/ces...re.aspx?id=960

 

Woah! That's alot of money! I could go down to the local junk yard and pull the entire axle out of a Mustang, that's why I asked. Plus, I've done axle switches before on a '64 Mustang... I wouldn't have a clue where to start on the new locker install. Thanks for the reply, though. Keep 'em coming!

 

The mustang axles are way different than the truck axle. If you want a limited slip and dont want to install a LM into your axle, go to a junkyard and pull a axle out of an f-150, it HAS to be a 97-03 axle. Any way you go its going to be somewhat expensive.

 

Good luck with that! IMO a quick session with a tape measure & eyeball should eliminate the idea of putting Mustang rear end in an F150. Besides, Limited Slip differentials were available as options for F150 & are fairly common. All you need to do is decipher the code either from the door sticker or tag on rearend to ID it. I'm also pretty "sure" Mustang's offered Limited Slip only as an option, presumably most Mustangs do not have LS.

FYI Positraction "POSI-Trac" was GM's trademark for their line of LS differentials.

 

For one, which engine do you have in your truck? That will determine which axle your truck has.

For two, Forget about putting any Mustang axle under the F150. They are much too narrow, they don't use leaf springs, and are considerably weaker than the truck's axle.

If you want a LS, go buy an aftermarket "clutchless" LS unit. Or, go to the junkyard and get a factory one out of a similar truck axle. It will be much, much cheaper than trying to make the Mustang axle work.

 

IMO "which engine" WILL NOT "determine which axle". Looks like Open or optional Limited Slip axles were for available w/any engine according to FORD sales lit.

You need to decipher the axle code from: the sticker in the door jam, tag on rear end, or if you have them, window sticker or build sheet, to determine which axle your truck has. If there's a chance the rear end might have been swapped or modified, you might need to open it up to ID parts within.

 

ATC is just thinking ahead. The engine will help determine if it is an 8.8 or a 9.75. If it is a 9.75, It might help kgpackrat to understand the difference in the truck and the Mustang rear. And is definitely needed for junk yard browsing a replacement.

 

Yes, I understand that the Mustang rear ends are different, what I was asking is if someone out there had had any luck converting one to fit a '99 F150. Sorry about the confusion. Dumb question anyway.

Anywho, About my current axle, here's the deal...

I have a '99 F150 4.2L V6. It used to be my fathers truck. It originally came with Limited Slip, but had to be replaced. At the time, the repair shop did not have the right axle in stock, and because my dad was on a time constraint, they put an axle from (what I was told) an '97 150 into my truck.

Here's all I know about the axle:

10- Bolt
Sticker with 828A written on it
Tag with "S828" stamped on it
9287 written above the driveshaft
F7TW-4025-AD left of driveshaft
24 AJ right of driveshaft
*(if facing the bumper under the truck)*

Any help would be great. I take it the general consensus is to just add POSI/LS to the existing axle?

 

If its a 5.4 it comes with the 9.75, if it has the 4.2 or 4.6 it has the 8.8. The motor can determine which axle it has, but it cannot determine if it is limited slip or not. Search for "axle code" on this forum, you will find the list of what gearing you have, etc. Look on the door jam it has a sticker, it will say AXLE and will say something like h9,b6,19,etc. It will be cheaper to go to a scrap yard or EBAY than to get a new one. Once you get one it would proabably be a good idea to have a professional install it, if you dont shim it right or something the axle can come apart.

 

i doubt a 4.2 L V6 is going to be a real "race car" at the track even with a LS rear end--- save your money. plan ahead and do something a few years down the road when you know more about this.

 

I figured out that it was a 10-Bolt FORD 8.8. In the process of inspecting, I realized I failed to copy down the second line of the axle ID tag which read:

3 55 88 9K26

I know that tells me it has 3.55 gears in it, but I'm not sure what the rest means.

How does this information help me? Well, I'm not sure, but it's the missing information that I was told I would need to find out where to go from here.

Is this an easy LS & 4.10 gear swap setup? Or do I need to go to the boneyard and just start looking for what I need?

 

I've heard this soooo many times! I had the option of getting a V8, but opted not too. There are plenty of performance items for this engine. If those little rice burners can do what they can with a 4-Banger, I can get what I want out of this truck.

And although I don't really know a whole lot about the rear axle in this truck, I am quite fluent in the engine realm of things. This engine is capable of more than most give it credit. I'm not looking to build a "race car", I just want more umph than I currently have.

I do understand where you're coming from, though. And I appreciate all of the replies!

 

Have you ever done a gear swap? If not then you have to pay someone to set it up for you(maybe $200-300)
I dont know what the rest of the tag means. If it was a LS it would say 3L55 or 3L73 or something like that.

 

If you want it to be quicker, the thing that wakes up these trucks more than anything else(for the same price) is a gear swap. These trucks have horrible gearing from the factory, if i ever get around to it im going to put 4.30s in my truck.