easiest way to check rear end gear ratio? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

2low72 · 11-21-2004, 09:49 PM

I know I've seen this in a thread before but couldn't find it.

Paul72 · 11-21-2004, 09:57 PM

Jack up the rear end and spin the tire. Count the number of revolutions of the driveshaft in 1 revolution of the tire. If both tires are off the ground, one revolution of the tire is needed. If only 1 tire is off the ground, spin it 2 times.

The number of driveshaft revolutions is your ratio (Just over 3 = 3.08, Almost 4 = 3.73, etc.)

Paul

2low72 · 11-21-2004, 10:06 PM

That's what i thought but wasn't sure

dwaite72lnghrn · 11-21-2004, 10:16 PM

I tape a string on the drive shaft, Then mark the tire with tape at the bottom. move the truck 1 tire revolution (a helper here will make it easier). Climb under and count the number of wraps the string has made and you have it. three wraps and a little 3.08, three and a half 3.5, three and 3/4 3.73, and so on.

Longhorn Man · 11-21-2004, 10:42 PM

I say count the teeth. The lube is probably 20 + years old anyways.

**BIG ORANGE** · 11-21-2004, 11:29 PM

Divide the ringear into the pinion!!!!

11-21-2004, 09:49 PM	#1
2low72 Registered User Join Date: Mar 2004 Location: Cheyenne, Wy Posts: 555	easiest way to check rear end gear ratio? I know I've seen this in a thread before but couldn't find it. __________________ 2014 GMC Yukon XL (Wifey's) 2004 Chevy Silverado Crew Cab Z71

11-21-2004, 09:57 PM	#2
Paul72 Registered User Join Date: Sep 2003 Location: Waterloo, IA Posts: 1,147	Jack up the rear end and spin the tire. Count the number of revolutions of the driveshaft in 1 revolution of the tire. If both tires are off the ground, one revolution of the tire is needed. If only 1 tire is off the ground, spin it 2 times. The number of driveshaft revolutions is your ratio (Just over 3 = 3.08, Almost 4 = 3.73, etc.) Paul __________________ '72 Chevy K20 - 383/4sp/205 - SOLD after 41 years in the family Next project - K/5 Tahoe (71 Blazer on 99 Tahoe chassis) Build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=789958

11-21-2004, 10:06 PM	#3
2low72 Registered User Join Date: Mar 2004 Location: Cheyenne, Wy Posts: 555	That's what i thought but wasn't sure __________________ 2014 GMC Yukon XL (Wifey's) 2004 Chevy Silverado Crew Cab Z71

11-21-2004, 10:16 PM	#4
dwaite72lnghrn Registered User Join Date: Jun 2002 Location: central pa Posts: 1,525	I tape a string on the drive shaft, Then mark the tire with tape at the bottom. move the truck 1 tire revolution (a helper here will make it easier). Climb under and count the number of wraps the string has made and you have it. three wraps and a little 3.08, three and a half 3.5, three and 3/4 3.73, and so on. __________________ 72 longhorn c30 502BB/th400/fact air/4.11rear/ custom camper 72 bug(the better half's) under reconstruction 2009 HHR aqua blue 71 GMC k20 350/sm465 2009 Chevy hd3500 6.6 Victory Red crew cab dually Dave & Jeanne

11-21-2004, 11:29 PM	#6
BIG ORANGE Senior Member Join Date: Oct 2001 Location: Lancaster S.C. Posts: 4,767	Divide the ringear into the pinion!!!! __________________ Things happen for a reason!

11-21-2004, 10:42 PM	#5
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	I say count the teeth. The lube is probably 20 + years old anyways.



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