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#1 |
Registered User
Join Date: Nov 2008
Location: edmonton, alberta
Posts: 293
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ring and pinion count- teeth versus GM stamp
afternoon, I just pulled the diff cover and counted teeth on my ring and pinion.
43 on the ring and 10 on the pinion. that should give me 4.30 rearend gearing right? There was GM stamping on the ring gear of 14:43 (along with some other number) which would indicate a 3.08 rear end, but the teeth count doesn't match up. Could a previous owner have swaped the ring gear but not the pinion? what gearing do I have do you think?
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![]() 76 Silverado, 2wd, long box, 350/th350, 3.42 posi, edelbrock performer 64cc heads, edelbrock 1405, 2101 intake, Hedman Headers, Comp Cam XE262 http://beerbreadbike.wordpress.com/ |
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#2 |
Registered User
Join Date: May 2009
Location: Motor City
Posts: 9,194
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Re: ring and pinion count- teeeth versus GM stamp
If you counted 43 and 10 (and counted correctly) then you absolutely have a 4.30:1 axle ratio.
I can't explain why the ring gear was stamped 14:43 if you are only counting 10 teeth on the pinion gear. It is not possible to swap the ring gear without swapping the pinion, because then the two gears would not mesh. K
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Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/ Last edited by Keith Seymore; 11-08-2009 at 06:27 PM. |
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#3 |
Still plays with trucks
Join Date: Jul 2009
Location: Spokane, WA
Posts: 3,556
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Re: ring and pinion count- teeeth versus GM stamp
Can you read the stampings on the end of the pinion gear?
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miSSed opportunity - ground up creation of an AWD 1994 454 SS that never was http://67-72chevytrucks.com/vboard/s...d.php?t=795577 69 C10 shortbed stepside 400 small block - built like what a super sport truck could have been 69 K20 lwb TBI 350 4L60E NP208 14-bolt Dana-44 w/disc 68 Camaro SS / RS 500hp 439 inch roller cam big block 4L80E 79 Malibu TPI 350 4L60 w/ Z28 steering & sway bars |
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#4 |
Registered User
Join Date: Nov 2008
Location: edmonton, alberta
Posts: 293
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Re: ring and pinion count- teeeth versus GM stamp
Unfortunately, it's all closed up now but I don't remember seeing any stamps on the end of the pinion, only on the ring.
I am pretty sure I counted properly but that ratio isn't one I've heard of before for these trucks. I must have miscounted. I wanted to take a look before I ordered new parts and my desired ratio- 3.73.
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![]() 76 Silverado, 2wd, long box, 350/th350, 3.42 posi, edelbrock performer 64cc heads, edelbrock 1405, 2101 intake, Hedman Headers, Comp Cam XE262 http://beerbreadbike.wordpress.com/ |
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#5 |
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![]() Join Date: Mar 2000
Location: Cypress, TX
Posts: 39,023
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Re: ring and pinion count- teeeth versus GM stamp
I think the 43 indicates your 4.30
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#6 |
One shot, one kill.
Join Date: Dec 2007
Location: Saratoga Springs NY
Posts: 859
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Re: ring and pinion count- teeeth versus GM stamp
Vtwin, you determined the ratio exactly right as Keith indicates, BUT, you counted wrong. The stamping is right, (I have never seen the stamping be wrong BTW) you have 3:08 just like mine. To the best of my knowledge (33 years as GM tech), GM never made a 4:30 ratio gearset. 4:10 & 4:56 are the only 4 series gearsets I am aware of. Jim
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1984 K20 350M engine with 465,000 miles. Well, it's finally done!! Almost 2 years of work, but it was really worth the effort. Little stuff left to do is mount winch, wet sand & buff out and build belly pan\running boards. Body work takes lots and LOTS of beer!!!! God, Guts and Guns made America and God, Guts and Guns will preserve it! The worst thing you could do is get into my sights, but that don't matter, you'll never know it, cause you'll never hear the shot ![]() |
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#7 |
Still plays with trucks
Join Date: Jul 2009
Location: Spokane, WA
Posts: 3,556
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Re: ring and pinion count- teeth versus GM stamp
4.88's were an optional gear ratio you could order on my 68 Camaro when it was new.
I had a 70 Buick GS 455 that had 4.33 gears and it was all stock so I think they were original.
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miSSed opportunity - ground up creation of an AWD 1994 454 SS that never was http://67-72chevytrucks.com/vboard/s...d.php?t=795577 69 C10 shortbed stepside 400 small block - built like what a super sport truck could have been 69 K20 lwb TBI 350 4L60E NP208 14-bolt Dana-44 w/disc 68 Camaro SS / RS 500hp 439 inch roller cam big block 4L80E 79 Malibu TPI 350 4L60 w/ Z28 steering & sway bars |
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#8 |
*************
![]() Join Date: Apr 2005
Location: Pensacola, FL
Posts: 17,846
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Re: ring and pinion count- teeth versus GM stamp
Jack it up. Mark a spot on the tire. Turn the pinion until the spot on the tire makes one revolution. If it's a 3.08, the pinion should only turn slightly over 3 times.
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#9 |
Registered User
Join Date: Nov 2003
Location: Waco TX
Posts: 247
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Re: ring and pinion count- teeth versus GM stamp
Hart, i have absolutely never got the tire method to work, and tried on many many different cars. Cars that ive put the ring and pinion in myself, and it was no where close to correct, both limited slip, and open diff. rearends
Is the truck running? There is a HUGE difference in 4.30's and 3.08s on the freeway. With a factory sized tire, and a non-overdrive tranny, you probably wouldnt be able to do 75mph
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#10 |
Still plays with trucks
Join Date: Jul 2009
Location: Spokane, WA
Posts: 3,556
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Re: ring and pinion count- teeth versus GM stamp
You should be about 2000 rpm with 3.08's and 30" tall tires and about 2900 rpm with 4.30 gears at 60 mph. Pretty easy to tell on the tachometer if you have one. About a 30% difference in RPM.
I'm over 3200 rpm at 60 mph with 5.13's and 32" tires. I'd love to have only 4.30 gears ![]()
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miSSed opportunity - ground up creation of an AWD 1994 454 SS that never was http://67-72chevytrucks.com/vboard/s...d.php?t=795577 69 C10 shortbed stepside 400 small block - built like what a super sport truck could have been 69 K20 lwb TBI 350 4L60E NP208 14-bolt Dana-44 w/disc 68 Camaro SS / RS 500hp 439 inch roller cam big block 4L80E 79 Malibu TPI 350 4L60 w/ Z28 steering & sway bars |
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#11 |
Registered User
Join Date: Nov 2008
Location: edmonton, alberta
Posts: 293
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Re: ring and pinion count- teeth versus GM stamp
Thanks guys,
Yeah, I definately miscounted. My rpms are too low at 60 mph.
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![]() 76 Silverado, 2wd, long box, 350/th350, 3.42 posi, edelbrock performer 64cc heads, edelbrock 1405, 2101 intake, Hedman Headers, Comp Cam XE262 http://beerbreadbike.wordpress.com/ |
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