Is there an easy way to tell if one has the Limited Slip differential in their truck? Is it specified in the VIN somehow or are there any markings on the rear end itself? I have a 99XLT 4x2 Sport with the 4.6 and auto trans. It was an off the lot purchase and I never did ask about it.

cd


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Silver 99 F150 XLT 4x2 Sport Extended Cab with Flare Sides...
Mods: K&N Air Filter, Tinted Side Windows, Reese Class 3, Airbox Mod's, Fiberglass Tonneau Cover, Alpine Deck & Subwoofer Processor, Zapco AG350 Amp, JL 10W0 (times 3) & 1 Farad Cap
Coming soon: Flowmaster 40 Series Catback System (Orderred), Spray-On Bed Liner

 

Post your VIN and the code from the tag on the drivers side door frame. There are some knowlegeable people on this site that have the code breakdown. You could also crawl under and look at the tag attached to the center section of the rear end but that is a messy job.

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97 F-150, 2WD, Reg Cab,Flareside,Dk Toreador Red, 4.6, 3.55 LS, EGR Bug Deflector, ******* Bed Cover, Bed Liner, XL Full Length Running Boards, Air Aid Kit, Gibson Single Out Cat Back, Superchips, TransGo Shift Kit, Hellwig Rear Sway Bar, Hellwig 2500# Overload Springs

 

They usually have letters accompaning the numbers. Or at least the ones I've seen inside the door post

 

corey, most likely not. Most trucks off the lot don't have this option (never figured out why). But it is possible.


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1999 Lariat SuperCab Flareside, Amazon Green with Silver trim, 5.4L, 4x2, 4 wheel disc/ABS, 3.55 limited slip, towing package, fog lamps, sliding rear window, captains chairs, keyless entry with alarm, spray-on bed liner, bug guard, and K&N. http://www.csc.calpoly.edu/~bfriesen/truck.html

 

Corey,

Someday if you happen to have a jack handy...get both rear wheels off of the ground (don't forget to block the fronts!). Now, with the trans in neutral, emergency brake off, rotate one wheel by hand. If the other one rotates in the same direction you have limited slip. If it stays still or goes in the opposite direction you don't have it. While you're at it you can find out the ratio as well...get some liquid paper or whatever and put a mark on the bottom of the driveshaft. Have a fried rotate the tire one complete revolution while you count how many times the driveshaft goes around. Driveshaft goes around almost exactly 3 times you've got a 3.08, 3 and a half times you've got a 3.55 etc.

 

There was a thread awhile back that dealt with that. If I remember correctly there is a tag on the differential that has a code giving ratio and whether it was an open or closed rear end. Something like:L355S is a 3:55 limited-slip. Someone will be along shortly to correct it if it's wrong.


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Red 99.5 Lightning,#0975,Born 5/6/99...Adopted 5/27/99 Chipped w/SuperChip Flipchip chip,Water Wetter, Mobil 1, Foglamp Covers, 13.573@101.08

 

Found it. https://www.f150online.com/f150board...ML/000162.html

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Red 99.5 Lightning,#0975,Born 5/6/99...Adopted 5/27/99 Chipped w/SuperChip Flipchip chip,Water Wetter, Mobil 1, Foglamp Covers, 13.573@101.08

 

Even better, I found a chart detailing the different rear-ends as well as the codes. I found the code for mine to be 19, which according to the chart is the 3.55 regular slip.

Here's the chart...

Code Ratio Weight Brand Type

12 2.73 3800 FORD REG
18 3.08 3800 FORD REG
19 3.55 3800 FORD REG
25 4.10. 5300 FORD REG
29 3.55 5300 FORD REG
35 4.10. 6250 FORD REG
39 3.55 6250 FORD REG
45 4.10. 7400 FORD REG
49 3.55 7400 FORD REG
65 4.10. 8250 FORD REG
69 3.55 8250 FORD REG
72 4.63 11000 DANA REG
73 5.13 11000 DANA REG
H5 4.10. 3800 FORD LIMITED SLIP
H9 3.55 3800 FORD LIMITED SLIP
H8 3.08 3800 FORD LIMITED SLIP
B5 4.10. 5300 FORD LIMITED SLIP
B9 3.55 5300 FORD LIMITED SLIP
C5 4.10. 6250 FORD LIMITED SLIP
C9 3.55 6250 FORD LIMITED SLIP
D5 4.10. 7400 FORD LIMITED SLIP
F5 4.10. 8250 FORD LIMITED SLIP


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Silver 99 F150 XLT 4x2 Sport Extended Cab with Flare Sides...
Mods: K&N Air Filter, Tinted Side Windows, Reese Class 3, Airbox Mod's, Fiberglass Tonneau Cover, Alpine Deck & Subwoofer Processor, Zapco AG350 Amp, JL 10W0 (times 3) & 1 Farad Cap
Coming soon: Flowmaster 40 Series Catback System (Orderred), Spray-On Bed Liner

 

Well, another way to find out is lightup the tires. One strip of rubber means non-Ls!

 

How would Ford check to verify the LS is working properly?

 

fast46triton, I like your suggestion. I was going to suggest he do the same thing... if my V-6 will spin the tires, his 4.6 surely will--and that's a good way to tell if he's got LS!! :-)

Mike

 

FREEZER: I looked at your web site, nice. How did you come up withthe weight of your truck? I weighed mine with 3/4 tank of gas and me in it and came up with 4720. Was yours the empty weight. I found an open military digital scale on the local Ari Force base so I can weigh it again anytime with an empty tank and me out. Just curious.


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97 F-150, 2WD, Reg Cab,Flareside,Dk Toreador Red, 4.6, 3.55 LS, EGR Bug Deflector, ******* Bed Cover, Bed Liner, XL Full Length Running Boards, Air Aid Kit, Gibson Single Out Cat Back, Superchips, TransGo Shift Kit, Hellwig Rear Sway Bar, Hellwig 2500# Overload Springs

 

Hey Matt in MO, where are you from?

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stock 98 XL, Reg. cab,4.6, Auto, Tow package, 255/70R16 on styled steel wheels,3.55LS, Black with chrome grille and bumpers! MODS: custom stereo by me, building speaker box was a !@#$%. K&N air filter w/ airbox mod, a complete keyless entry system.