when i bought my truck, i never asked the previous owner if he ever changed the gears in the rearend. now that i have had my tires on for a while now, i want to install lower gears in order to gain some of that lost power. i believe my truck came with 2.73's standard, but how can i find out for sure what my gear ratio is? any help is appreciated!

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1989 F-150 XLT Lariat: 2WD 302 5spd[*]Performance Accessories 3" Body Lift[*]33x12.50.15 BFG A/T's on 15x10 AR Rims[*]Rancho Steering Stabilizer[*]Rancho RS 5000 Shocks[*]K&N Air Filter[*]Gutted Cats with Straight Pipes For Now...

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There should be a sticker either on the door or on the cab in the door latch area of the drivers side. This will list, among other things, an axle code. Post the code, and someone will probably be able to tell you the axle ratio.

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2000 F150 XLT 4X4 Off Road 5.4L Reg. Cab 3.55

Performance Enhancemets:
K&N
WMS Velocity Tube
Gibson Sweptside

Audio Enhancements:
All of the above, plus
Sony C7000X HU
Cerwin-Vega SS2502 components(Front)
Blaupunkt PCxp573s(Rear)

Radio-delay mod

Other Enhancements:
Extang Black Max Tonneau Cover
Keyless Entry Keypad
Eurolite Xenon Fusion Bulbs - Headlights and Fogs

 

in the door label under axle it says 18. that means that the truck came from the factory with 3.08 gears, right? how can i find out if one of the previous owners changed the gears? any help is appreciated!

[This message has been edited by Donate54 (edited 06-02-2001).]

 

Donate54- Yes 18 is open,3.08. If it has been changed you can get the ratio by dividing the number of teeth on the ring gear by the number of teeth on the pinion gear. If you want to "estimate" it, first determine if it has been changed to a posi by jacking up one wheel and trying to turn it. If it turns, it's open, if it doesn't, it's a posi (if unit is working correctly). Next is ratio estimation: Open differential; jack one tire, rotate tire 2 revolutions while measuring drive shaft revolutions, this number of drive shaft revolutions is your approximate ratio. Posi differential; jack both tires, rotate tire 1 revolution while measuring drive shaft revolutions, this number of drive shaft revolutions is the approximate ratio. Turning the tire twice this much and dividing the drive shaft revolutions by 2 will increase accuracy.

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2000 F-150 XL, RC, LB, 5.4L, 4R70W, 4.10LS,
Class III tow, Payload #3, & Convenience pkgs.,
4-wheel disc/ABS, Chestnut/Parchment 40/60,
Ford bedliner w/Paintsaver & gas/wheel/spare locks,
K&N F.I.P.K. w/Outwears pre-filter, Superchip,
Dynomax ultra-flow welded 3" cat-back w/ 3" Y-pipe,
Hellwig front & rear anti-sway bars, Rancho RS 9000s,
Pirelli Scorpion Zero 275/60/16s, Mobil 1, K&N oil filter.