If one gear is 41 teeth....is it 3:07 or 3:73? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

67Blacksheep · 04-08-2002, 07:56 PM

Is knowing that the large gear is 41 teeth enough information to determine rear-end size. 3:07 or 3:73???

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67 Chevy C20 LB Stepside,
350 4-bolt with goodies.

Mike C · 04-08-2002, 08:10 PM

No as a 4.10 gear set is 41 and 10. On the outside of the ring gear are stamped numbers including the number of teeth of the pinion and ring. They will be together about 1/4" apart or so. Wipe the gear off with a rag and they should be obvious.

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70 GMC 3/4 ton Sierra Grande 402/TH400
72 Jimmy 4WD 4spd 4" & 35's
64 Corvette Coupe
68 Camaro 'vert TPI & TH700
69 Z/28 355 12.6's @110
72 Datsun 240Z-ol' reliable

Gordo · 04-08-2002, 08:11 PM

If the pinion has 11 teeth and your ring gear has 41, you have 3:73's.

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1971 C10 swb stepside 350/700R4/3.73posi
Killingworth, Connecticut

67Blacksheep · 04-08-2002, 08:14 PM

Thank you gentlemen...I take it the 3:07 is out of the loop now?? It would be good if that is the case!! I will check the gear for the numbers!!

KD · 04-08-2002, 08:22 PM

I just blew the rear end out of the Tahoe and counted 41 teeth on the ring gear and 11 on the pinion (41 divided by 11 = 3.727272 or 3.73 gears),I beleive Gordo is correct.

*Fast68Chevy* · 04-09-2002, 02:34 AM

11-41 is 3.73 14-43 is 3.07 stuff like that is easy to memorize after a few times
41-18 is 2.28 thats in some other gm axles, not 12 bolt though

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Randy- Lincoln, IL
r68c30@hotmail.com

-71 C-10 350/CH465/3.07 12 bolt 3.07/ trying to assemble! *Life and time permitting* :P
-84 Z28 Camaro 5.0L 700R4, 3.73 rear
-84 Firebird SE 2.8L. 5 speed Borg Warner
-82 Firebird 350/TH350

*parting out 5.0LTPI '81 cutlass supreme brougham, and have lots of '67-87 parts of all kinds to sell or trade*
*Paint is overrated
© RSS Enterprises 2000

[This message has been edited by Fast68Chevy (edited April 12, 2002).]

DarkFox1 · 04-09-2002, 01:21 PM

I'd guess its a 3.73 yes... did you look on the gear itself tho? obviously if you had it out to count gears.. look for a number on the side of your ring gear something like 11 41 or 41 11 then go to www.ringpinion.com and play with their gear ratio calculator. It should tell you appx. what you have. Standard in v8s was 3.07 and standard in 6s was 3.73.. or at least I think thats right.

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Projects
Belair '71 C10 LWB to SWB conversion:C10 project page
65Chevelle pics coming soon

texnician01 · 04-09-2002, 04:24 PM

I have noticed that noone ever takes the easy way and just turns the tires. Jack up one side, put it in neutral, turn the tire 2 full turns and count how many times the driveshaft turns. that will give you a close approximation. if it turns 3 times and a little bit more then it is a 3.07 if it turns 3 times and then about 3/4 of a turn it is a 3.73 if it turns 4 times and a little more then they are 4.11's . and if it turns HARD then it most likely is a posi, or very very neglected. Seems the easiest to me then you don't have to mess with 90wt and you can still use the axle without having to mess around and put on a gasket and refill it. just my $.02

Mike C · 04-11-2002, 07:59 PM

Rotating the tires only works with a posi. Otherwise, when you turn one, the other turns the opposite way and the driveshaft just sits there. It is possible if you leave one tire on the ground, rotate the other tire and count driveshaft revolutions. You then either multiply or divide by 2, I forget which, but I think it is multiply to get the ratio. The differential effect of the spider and side gears is the monkey in this mess.

------------------
70 GMC 3/4 ton Sierra Grande 402/TH400
72 Jimmy 4WD 4spd 4" & 35's
64 Corvette Coupe
68 Camaro 'vert TPI & TH700
69 Z/28 355 12.6's @110
72 Datsun 240Z-ol' reliable

Yellow Cheyenne · 04-11-2002, 08:19 PM

I believe that's why he said to jack up one side. Yes, only one tire can turn and it is easiest to turn it two full revolutions. Texnicians01's method and description is correct.

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'72 Cheyenne. AC, PS, PB, Rear slider window, tilt. Light yellow (grapefruit yellow according to new sales literature from '72)
'70 Olds 442 convertible
'70 Olds Rallye 350
'72 Olds Cutlass convertible

[This message has been edited by Yellow Cheyenne (edited April 11, 2002).]

*Fast68Chevy* · 04-11-2002, 09:41 PM

it stil doesnt always work though, i have had problems of turning one wheel with other on ground and no posi and it only spinning half the revolutions then you gotta multiply by two,
the teeth count of both gears is on the outer edge face of the ring gear, spin an axle with truck jacked and you will see it, and the year and month also

3.07 cam in the 307 and 350 trucks with auto and 4 speed trannies and also with BB engine with all trannies and in the 4x4 also with auto or 4 speed, it was not engine that mattered, it was actually the tranny ordered that determined axle installed

R

texnician01 · 04-12-2002, 04:15 PM

Thanks yellow,

You have to turn the tire TWO FULL REVOLUTIONS and then you don't have to multiply by 2.

------------------
1969 C-10 292 I-6 4 spd in the middle of a restoration. going to get a 327 and 3.07 gears but keeping all of the original parts so I can put it back to original later on down the road.
55 chevy 4 door 150
47 Willys CJ-2A

Longhorn Man · 04-12-2002, 04:22 PM

It is easier to do it right, there is no guessing, no problems, and it is good preventive maintnance. How long you think that oil has been in there? I'll guess since the '80's at best.
Drain it and count the teeth. You just can't do wrong that way.

------------------
'69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man
I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it.
FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite.
If you need a pic posted, E-mail me at longhornmail@yahoo.com
Andy, in Columbus Ohio

67Blacksheep · 04-13-2002, 10:18 AM

Gents-
Thanks for all the info. The gear teeth were stamped right on the ring at 11-41. It is a great day in the flock. Something finally went right!!! 3:73 is exactly what i wanted! If only it were posi....oh well, can't have it all.

Thanks again!

------------------
67 Chevy C20 LB Stepside,
350 4-bolt with goodies.

04-08-2002, 07:56 PM	#1
67Blacksheep Registered User Join Date: Mar 2002 Location: Ohio Posts: 135	If one gear is 41 teeth....is it 3:07 or 3:73? Is knowing that the large gear is 41 teeth enough information to determine rear-end size. 3:07 or 3:73??? ------------------ 67 Chevy C20 LB Stepside, 350 4-bolt with goodies. __________________ '94 GMC Seirra Ext. Cab '67 Formula Firebird '89 GSX-R 750

04-08-2002, 08:10 PM	#2
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,709	No as a 4.10 gear set is 41 and 10. On the outside of the ring gear are stamped numbers including the number of teeth of the pinion and ring. They will be together about 1/4" apart or so. Wipe the gear off with a rag and they should be obvious. ------------------ 70 GMC 3/4 ton Sierra Grande 402/TH400 72 Jimmy 4WD 4spd 4" & 35's 64 Corvette Coupe 68 Camaro 'vert TPI & TH700 69 Z/28 355 12.6's @110 72 Datsun 240Z-ol' reliable __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

04-08-2002, 08:11 PM	#3
Gordo Registered User Join Date: Jan 2001 Location: Killingworth, CT. USA Posts: 3,378	If the pinion has 11 teeth and your ring gear has 41, you have 3:73's. ------------------ 1971 C10 swb stepside 350/700R4/3.73posi Killingworth, Connecticut __________________ 1971 C10 swb stepside 350/700R4/3.73posi (retired as of 4/22/03) 1998 S10 short bed 2002 S10 Blazer 1942 Oldsmobile 1958 Massey Harris Pony 1951 Wife Killingworth, Connecticut May those who love us, love us, any of those who do not love us, may God turn their hearts. And if God is unable to turn their hearts, may he turn their ankles so we may know them by their limping. A man who works with his hands is a laborer; a man who works with his hands and his brain is a craftsman; but a man who works with his hands and his brain and his heart is an artist.

04-08-2002, 08:14 PM	#4
67Blacksheep Registered User Join Date: Mar 2002 Location: Ohio Posts: 135	Thank you gentlemen...I take it the 3:07 is out of the loop now?? It would be good if that is the case!! I will check the gear for the numbers!! __________________ '94 GMC Seirra Ext. Cab '67 Formula Firebird '89 GSX-R 750

04-08-2002, 08:22 PM	#5
KD Truck Nut Join Date: Mar 2000 Location: Big Lake,MN,US Posts: 134	I just blew the rear end out of the Tahoe and counted 41 teeth on the ring gear and 11 on the pinion (41 divided by 11 = 3.727272 or 3.73 gears),I beleive Gordo is correct. __________________ '70 3/4 manual w/350 4.56's .Doing a ground up on a '67 4x4 4"lift.

04-09-2002, 02:34 AM	#6
Fast68Chevy Account Suspended Join Date: May 2000 Location: IL Posts: 0	11-41 is 3.73 14-43 is 3.07 stuff like that is easy to memorize after a few times 41-18 is 2.28 thats in some other gm axles, not 12 bolt though ------------------ Randy- Lincoln, IL r68c30@hotmail.com -71 C-10 350/CH465/3.07 12 bolt 3.07/ trying to assemble! Life and time permitting :P -84 Z28 Camaro 5.0L 700R4, 3.73 rear -84 Firebird SE 2.8L. 5 speed Borg Warner -82 Firebird 350/TH350 parting out 5.0LTPI '81 cutlass supreme brougham, and have lots of '67-87 parts of all kinds to sell or trade *Paint is overrated © RSS Enterprises 2000 [This message has been edited by Fast68Chevy (edited April 12, 2002).]

04-09-2002, 01:21 PM	#7
DarkFox1 in WAY over my head Join Date: Sep 2001 Location: Douglasville GA Posts: 923	I'd guess its a 3.73 yes... did you look on the gear itself tho? obviously if you had it out to count gears.. look for a number on the side of your ring gear something like 11 41 or 41 11 then go to www.ringpinion.com and play with their gear ratio calculator. It should tell you appx. what you have. Standard in v8s was 3.07 and standard in 6s was 3.73.. or at least I think thats right. ------------------ Projects Belair '71 C10 LWB to SWB conversion:C10 project page 65Chevelle pics coming soon

04-09-2002, 04:24 PM	#8
texnician01 Senior Member Join Date: Mar 2002 Location: 12 Miles South of Des Moines, Iowa Posts: 359	I have noticed that noone ever takes the easy way and just turns the tires. Jack up one side, put it in neutral, turn the tire 2 full turns and count how many times the driveshaft turns. that will give you a close approximation. if it turns 3 times and a little bit more then it is a 3.07 if it turns 3 times and then about 3/4 of a turn it is a 3.73 if it turns 4 times and a little more then they are 4.11's . and if it turns HARD then it most likely is a posi, or very very neglected. Seems the easiest to me then you don't have to mess with 90wt and you can still use the axle without having to mess around and put on a gasket and refill it. just my $.02 __________________ 69 C-10, 340HP 327 55 chevy 4 door 150 47 Willys CJ-2A 05 Harley Night Train 06 1200 Sportster (Wife's bike) 70 Honda CL350 OIF2 & OIF7 Veteran Nathan & Tiffany

04-11-2002, 07:59 PM	#9
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,709	Rotating the tires only works with a posi. Otherwise, when you turn one, the other turns the opposite way and the driveshaft just sits there. It is possible if you leave one tire on the ground, rotate the other tire and count driveshaft revolutions. You then either multiply or divide by 2, I forget which, but I think it is multiply to get the ratio. The differential effect of the spider and side gears is the monkey in this mess. ------------------ 70 GMC 3/4 ton Sierra Grande 402/TH400 72 Jimmy 4WD 4spd 4" & 35's 64 Corvette Coupe 68 Camaro 'vert TPI & TH700 69 Z/28 355 12.6's @110 72 Datsun 240Z-ol' reliable __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

04-11-2002, 08:19 PM	#10
Yellow Cheyenne Registered User Join Date: Jun 2001 Location: Eastern Kansas Posts: 488	I believe that's why he said to jack up one side. Yes, only one tire can turn and it is easiest to turn it two full revolutions. Texnicians01's method and description is correct. ------------------ '72 Cheyenne. AC, PS, PB, Rear slider window, tilt. Light yellow (grapefruit yellow according to new sales literature from '72) '70 Olds 442 convertible '70 Olds Rallye 350 '72 Olds Cutlass convertible [This message has been edited by Yellow Cheyenne (edited April 11, 2002).] __________________ '72 Cheyenne. AC, PS, PB, Rear slider window, tilt. Light yellow (grapefruit yellow according to new sales literature from '72) '56 Chevy short step V-8 (My dad bought it new!!) '70 Olds 442 convertible '70 Olds Rallye 350

04-11-2002, 09:41 PM	#11
Fast68Chevy Account Suspended Join Date: May 2000 Location: IL Posts: 0	it stil doesnt always work though, i have had problems of turning one wheel with other on ground and no posi and it only spinning half the revolutions then you gotta multiply by two, the teeth count of both gears is on the outer edge face of the ring gear, spin an axle with truck jacked and you will see it, and the year and month also 3.07 cam in the 307 and 350 trucks with auto and 4 speed trannies and also with BB engine with all trannies and in the 4x4 also with auto or 4 speed, it was not engine that mattered, it was actually the tranny ordered that determined axle installed R

04-12-2002, 04:15 PM	#12
texnician01 Senior Member Join Date: Mar 2002 Location: 12 Miles South of Des Moines, Iowa Posts: 359	Thanks yellow, You have to turn the tire TWO FULL REVOLUTIONS and then you don't have to multiply by 2. ------------------ 1969 C-10 292 I-6 4 spd in the middle of a restoration. going to get a 327 and 3.07 gears but keeping all of the original parts so I can put it back to original later on down the road. 55 chevy 4 door 150 47 Willys CJ-2A __________________ 69 C-10, 340HP 327 55 chevy 4 door 150 47 Willys CJ-2A 05 Harley Night Train 06 1200 Sportster (Wife's bike) 70 Honda CL350 OIF2 & OIF7 Veteran Nathan & Tiffany

04-12-2002, 04:22 PM	#13
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	It is easier to do it right, there is no guessing, no problems, and it is good preventive maintnance. How long you think that oil has been in there? I'll guess since the '80's at best. Drain it and count the teeth. You just can't do wrong that way. ------------------ '69 G.M.C. 350/350. Trying to clean up the left over damage from the Dope-Smokin-Old-Man I've been dubbed the Longhorn Freak/Fanatic/Expert, I just hope I can live up to it. FINALLY got the HORNIAC...a '70 one ton Longhorn with a Pontiac 350/350 and lots of 'personality'. Check out The Longhorn Webite. If you need a pic posted, E-mail me at longhornmail@yahoo.com Andy, in Columbus Ohio

04-13-2002, 10:18 AM	#14
67Blacksheep Registered User Join Date: Mar 2002 Location: Ohio Posts: 135	Gents- Thanks for all the info. The gear teeth were stamped right on the ring at 11-41. It is a great day in the flock. Something finally went right!!! 3:73 is exactly what i wanted! If only it were posi....oh well, can't have it all. Thanks again! ------------------ 67 Chevy C20 LB Stepside, 350 4-bolt with goodies. __________________ '94 GMC Seirra Ext. Cab '67 Formula Firebird '89 GSX-R 750



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