Checking for gear ratio - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Chevyguy111786 · 01-17-2005, 12:02 AM

Hey guys,
I sold a rear end to a fellow board member, thinking it was a 3.73 gearing, it wasn't. so i have a few more and want to make my wrong right. how can i check my other diffs to make sure it's 3.73. i'm fine with opening it up and all that. so if one could point me in the right direction that would be wonderful.

Longhorn Man · 01-17-2005, 01:27 AM

pop the cover off, and there will be 2 gears. Count the teeth on the driven gear (big one) and divide the number from the drive gear, and that'll be the ratio.

Chevyguy111786 · 01-17-2005, 11:30 AM

i knew it was somethin easy....thanks much

poff · 01-17-2005, 06:03 PM

Typically the ring gear will have a code on it. It will have the manufacture date, the ring gear tooth count and the pinion tooth count. I do not know the order but it is something like this: 5/74 41 10 - May of 1974, 41 tooth ring gear, 10 tooth pinion. 41/10=4.10 etc.

Chevyguy111786 · 01-18-2005, 05:09 PM

yeah it had 41/11
which rounded out to 3.73...or something...but it was 3.73 lol...thanks guys

01-17-2005, 12:02 AM	#1
Chevyguy111786 Registered User Join Date: Apr 2003 Location: Garland, Texas Posts: 1,127	Checking for gear ratio Hey guys, I sold a rear end to a fellow board member, thinking it was a 3.73 gearing, it wasn't. so i have a few more and want to make my wrong right. how can i check my other diffs to make sure it's 3.73. i'm fine with opening it up and all that. so if one could point me in the right direction that would be wonderful.

01-17-2005, 06:03 PM	#4
poff Registered User Join Date: Dec 1999 Location: san diego, ca Posts: 546	Typically the ring gear will have a code on it. It will have the manufacture date, the ring gear tooth count and the pinion tooth count. I do not know the order but it is something like this: 5/74 41 10 - May of 1974, 41 tooth ring gear, 10 tooth pinion. 41/10=4.10 etc. __________________ '70 K-20 San Diego, CA

01-17-2005, 01:27 AM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	pop the cover off, and there will be 2 gears. Count the teeth on the driven gear (big one) and divide the number from the drive gear, and that'll be the ratio.

01-17-2005, 11:30 AM	#3
Chevyguy111786 Registered User Join Date: Apr 2003 Location: Garland, Texas Posts: 1,127	i knew it was somethin easy....thanks much

01-18-2005, 05:09 PM	#5
Chevyguy111786 Registered User Join Date: Apr 2003 Location: Garland, Texas Posts: 1,127	yeah it had 41/11 which rounded out to 3.73...or something...but it was 3.73 lol...thanks guys



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