Changing from open diff to limited-slip diff

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Oct 9, 2002 | 10:10 PM

dscheidt

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From: Stuarts Draft

Changing from open diff to limited-slip diff

I just purchased a 1996 XLT 4x2 with 4.9L 6-cyl & 5-speed. The axle code is 19 which is 3.55 open (regular) differential in an 8.8 housing. I went to a Ford dealer to ask for a price on a limited-slip differential and he said that I can't just change the differential. He stated that I would need a whole new housing, gears, axles, etc. He stated that the conversion would be over $1000. Is this true? I like the 3.55 gearing, I just want a true 2-wheel drive by having a limited slip rear-end. If I can just change the differential, does anyone know if the 31-spline differential in the Ford Racing Performance Parts catalog can be used in a 1996 F-150. The part number is M-4204-F318. It is described as a 31-tooth Traction-Lok differential for 8.8" axle. Any help is greatly appreciated. What parts would I need to purchase to do the swap?

Thanks,
Dean

Oct 9, 2002 | 11:31 PM

heathdaily

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From: kansas

Changing from open diff to limited-slip diff

Sounds like fordman is either trying to rip you off or he's quoting it like it was a repair. When repairing you start off assuming it's all trashed. Still the housing almost never needs replacing.

The M-4204-F318 should fit fine. I'll have one in my 92 F-150 by the end of the weekend.

Assuming the rest of your rear end is in good shape, you will only have to replace the diff carrier bearings. These could be re-used but I'd not reccomend it. Also reccomended is a shim set for setting proper backlash after re-installing the ring gear.

If you've no experience with this, I highly reccomend getting help from someone with actual experience. Special tools required. This can be done by a properly prepared amatuer, but your success rate will be much higher with someone who's done it before.

Did you know Summit is a Ford Motorsports Dealer?
I got my invoice right here.
256.95 for what they call the FMS-M4204F318 plus7.95 handling.
Cheapest I found any other brand anywhere was 310.00 plus 40.00 shipping.

Good luck.
And don't get caught "testing" that new diff.

Oct 9, 2002 | 11:35 PM

Polkat

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From: CA

Changing from open diff to limited-slip diff

Just another typical example of Ford's excellent technical training for it's staff!! NO! You don't need any of that stuff, and yes, you can use the limited slip in the catalog as long as your present axles are 31 spline. Or you can go to a Lock Right by Powertrax if you want a true lock while going straight ahead.

Oct 9, 2002 | 11:43 PM

heathdaily

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From: kansas

Changing from open diff to limited-slip diff

Yeah I shoulda thought of that. It'd be alot easier to install in your truck. The whole diff stays in the truck. You just pull the guts out of the old diff and replace. No carrier shims, no special tools. All you'd need for supplies is new gear oil, and replace the gasket or use silicone for a seal.

Oct 10, 2002 | 12:51 PM

MustangGT221

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From: Topsfield, MA

Changing from open diff to limited-slip diff

Stop stop stop, before you go out and buy an expensive new one, check ebay or junk yard. I bought a used LS (Ford's traction Lok) for 50 bucks(ebay)! The rebuild kit for it is about 80-90 bucks and is simple. By doing so you get a like-new LS for 140 bucks! As long as it's a 31 spline 8.8 LS you're fine. Mine came from an explorer. Mustang and thunderbirds used 28 spline axles so be a little careful. At the junk yard you might have to open up the diff cover on an axle to look. Here are some links to help you out.

https://www.ford-trucks.com/dcforum/DCForumID27/2253.html
https://www.ford-trucks.com/dcforum/DCForumID27/1818.html

Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster Exhaust, Sunroof, Clear corners w/ Diamond headlights, CD player with 2 10" subs and some 32" BFG Muds

.

Thats it for now, saving for a stang. Check out my Gallery for a look-see.

Justin - One Happy FTE Member

Oct 10, 2002 | 12:52 PM

MustangGT221

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Joined: Nov 2001

Posts: 14,947

Likes: 6

From: Topsfield, MA

Changing from open diff to limited-slip diff

For the first link, the installation is the same for the 7.5" rear diff and the 8.8" rear diff, so don't worry about that.

Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster Exhaust, Sunroof, Clear corners w/ Diamond headlights, CD player with 2 10" subs and some 32" BFG Muds

.

Thats it for now, saving for a stang. Check out my Gallery for a look-see.

Justin - One Happy FTE Member

Oct 10, 2002 | 01:07 PM

MustangGT221

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Joined: Nov 2001

Posts: 14,947

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From: Topsfield, MA

Changing from open diff to limited-slip diff

With just a quick search under "ford 8.8" I found these two, lots more to look through.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1866773325
On this one, you might want to make sure what exactly he means. There is no high-torque one that i know of. Sometimes people install 4 clutch disks per side vs the stock 3 disks, which makes it more agressive but thats the only thing I can think of.

This one is nice:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1867017485

Primary rig is Green Thunder:
95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster Exhaust, Sunroof, Clear corners w/ Diamond headlights, CD player with 2 10" subs and some 32" BFG Muds

.

Thats it for now, saving for a stang. Check out my Gallery for a look-see.

Justin - One Happy FTE Member