trans drive/driven gears
Thread Starter
Racer
Joined: Feb 2007
Posts: 337
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From: Clyde Ohio
trans drive/driven gears
Have 82 with stock 2.87 rear, 255/50-15 radial Ta's, so 27.1 diameter tire. My driven gear is the green 42 and drive I believe was yellow 19. I used a calculator and it said my driven should be a 40 tooth. My speedometer reads about 10mph fast at 60 and consistently gains as the mph increase. This tells me the driven is the wrong gear, but the larger driven you go doesn't that decrease your speedometer ? If I'm 2 teeth to big now shouldn't it be reading lower mph's or am I not figuring this correctly ? Does anyone know what gears are in the stock 82 tranny also...
Race Director
Joined: May 2006
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the forumla is driven gear over drive gear, 42/19 = 2.21 revolutions of the driven gear for one of the drive gear. The 40/19 = 2.10 revolutions of the driven gear for one of the drive gear. Thus the 40 tooth gear will reduce the speedometer reading.
Race Director
Joined: Apr 2009
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From: Charlotte NC
There were two types of differential ratios...so there is more than one set-up on the gears. I have that info in my factory parts manual...but it is at work...and would not matter in your case...because if you use the speedometer gear calculator...it will tell you what you need...as you know...when you know what the drive gear teeth number is and what the driven gear will have to be.
http://corvettec3.ca/axle.htm
DUB
http://corvettec3.ca/axle.htm
DUB
Race Director
Joined: Apr 2009
Posts: 19,294
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From: Charlotte NC
AS WRITTEN IN THE GM PARTS ILLUSTRATION CATALOG
The drive gear is a 19 tooth yellow gear...it is used in all applications.
2.72 alxe:
P225/70/15 tires uses a 39 tooth brown gear and the sleeve or sensor is 22512340
P255/60/15 tires uses a 40 tooth black gear and teh sleeve or sensor is a 22512339
2.87 axle:
P225/70/15 tires uses a 41 tooth yellow gear and the sleeve or sensor is 22512339
P255/60/15 tires uses a 42 tooth black gear and the sleeve or sensor is a 22512339
DUB
The drive gear is a 19 tooth yellow gear...it is used in all applications.
2.72 alxe:
P225/70/15 tires uses a 39 tooth brown gear and the sleeve or sensor is 22512340
P255/60/15 tires uses a 40 tooth black gear and teh sleeve or sensor is a 22512339
2.87 axle:
P225/70/15 tires uses a 41 tooth yellow gear and the sleeve or sensor is 22512339
P255/60/15 tires uses a 42 tooth black gear and the sleeve or sensor is a 22512339
DUB
