'91 rear end gear ratio

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Does anyone know what gearing comes standard on the '91's because my frind I met in Texas thought he had 4:10's but his pulls further in each gear and has a top speed of 5-7mph faster than mine. His original window sticker did not say what the gear ratio was. He doesn't think it has the 3:55's because it will only go 90-couple mph.

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Mine: '93 250 LE 4x4 5spd 4:10 Pwr win/loc/mir,cruise,strait piped,diamond plate tool box, CB, 16x10" AR rims, 285/75/16 Bf goodrich, US Gear E-Brake,Fuller Roadranger shifter, PW injectors, K&N. "wirenut_21529" on Yahoo Messenger
Moms:'96 Ford B-Series school bus (5. 9 Cummins!)I'm gonna Bomb it!
Dads:'94 GMC 2500 6. 5L Turbo

 

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Sounds like 3:54 to me. I top out in the low 90's. Mine is stamped on a tag on the left edge of the rear diff cover.

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'93 W250, LE, CC, 4x4, 5spd. , Cummins, K&N, 16cm turbo, Power Wagon injectors, Professionaly rebuilt and calibrated pump, straight exhaust, Lund visor w/lights, 5th wheel, Gooseneck, H. D. rear hitch, Aluminum everything. My Rigs

 

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Hey Wirenut.

Nice road trip story. Let the turbo whine!


The 4. 10 gear ratio would appear as an extra cost item on the window sticker.

With 4. 10's I get about 70 mph at 2500 rpm and 85 is top speed at 3000 rpm (no load at 3250).

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'93 W350 Club Cab, Bright White, 5 sp. , 130K, Factory Options: LE, 4. 10 Limited Slip, 7600 lb. rear springs, tachometer, front stabilizer bar. Mods: Banks stinger plus, Linex bedliner, 25,000 lb gooseneck ball, 10,000 lb receiver, Tekonsha brake controller, POWER WAGON injectors-WAY faster than stock!.

 

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IS it an early or late '91? Does it have manual or automatic transmission? My EARLY '91 came standard with a 3. 07 differential, and with A/T, topped out at 80 MPH. Early '91's had no OD option with automatic transmission, so the 3. 07 was necessary to maintain reasonable freeway speeds.

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Early '91 250, 727 AT, 307 rear...
Banks Stinger exhaust, intercooler...

 

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Wirenut-I have a 1 ton with the dana 70 rear axle. I have 3. 54's front and rear. I don't have a tachometer yet, but I seem to run out of gears before I run out of power. I see between 95 and 100mph before this happens, though. There should be a tag on the differential case cover with all the info for the ratio, unless someone removed it.

 

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You could also check to see what the gear ratio is by marking (chark or something) the driveshaft in one spot and also the tire in one spot. Then rotate the tire 1 full turn and watch how many times the driveshaft turned around. You will not get an Exact amount but very close to what the ratio may be. Something like driveshaft turning 4 turns would be a 4. 10 gear.